The best things in life may be free. But can you really be comfortable running key parts of your business on software you've downloaded gratis? The short answer: yes. New and increasingly powerful products are being made available every day free of charge--and you no longer need a degree in computer programming to make them work. In some cases, it's being offered by open-source companies looking to draw as many users as possible into the development process. But mainstream outfits are giving it away too, hoping to make money on the upsell or a service contract. Whatever the reason, more businesses are taking advantage of the bargain; 15 percent of U.S. businesses with 100 to 1,000 employees use an open-source application, and 11 percent use free Web-based applications, according to Jupiter Research. Here are six products that we think truly give you something for nothing.

Best for... Managing projects

What it is: Web-based project-management and collaboration software

Why it's cool: It's simple to use and your entire team can be up and running in minutes--with message boards, to-do lists, meeting schedules, and other useful tools, including a collaborative document editor and secure group chat.

Drawbacks: Basecamp is not designed to be a heavy-duty planning tool, so it may not meet the needs of some project managers. In other words, it's better for running a marketing campaign or consulting project than the development of a jet aircraft.

Price: Free, for one project at a time, with no file sharing. Basic business pricing starts at $24 a month for 15 projects at a time and 200 megabytes of file-sharing storage, and runs up to $149 a month for unlimited projects, data encryption, and 5 gigabytes of file storage. All versions have a 30-day free trial.

Best for... Making presentations

What it is: A Web-based presentation tool, à la PowerPoint. Because it's Web-based, there's no need for presentation software on your computer to view slides.

Why it's cool: Using a Web browser, you can create, open, and view a presentation, or print it, from any computer with Internet access. Remote usage is easy, so anyone on a conference call can follow along in real time without a separate Web conferencing tool. Offers free storage for presentations, so you don't have to lug your laptop to all of your meetings.

Drawbacks: Lacks wipes, transitions, and other sophisticated presentation techniques (though because the technology is open source, you could write your own, or get someone to write it for you).

Price: Free

Best for... Managing your customers

What it is: A full-fledged customer relationship management application

Why it's cool: SugarCRM is a free alternative to pricey systems offered by Seibel and (NYSE:CRM). Among its features: account management and sales-lead development tools, automatic e-mail campaigns, customer support management, and reporting tools to measure the effectiveness of a campaign. It's open source, so you can customize any part of the code to meet your needs.

Drawbacks: While nontechies can easily use some of the tools, getting the most out of the program probably requires the help of someone with technical knowledge.

Price: Free. A hosted version with more features, and support, costs $40 per month per user, or a $239 per user per year subscription fee (five-license minimum). A version with still more features that can be hosted on your server costs $75 per month per user or $449 per user per year.

Best for... Staying in touch

What it is: Instant messaging software

Why it's cool: Jabber makes instant messaging as universal as e-mail. Its protocols connect to every other protocol, on almost any platform, so you can send messages to people on Yahoo (NASDAQ:YHOO), MSN, ICQ, or any other IM service. It's open source, and more than 2,400 developers have contributed to it, creating constant upgrades for features, including group chat and RSS readers.

Drawbacks: Aside from message boards, Jabber offers no support. Getting help means going to an outside vendor--such as Wildfire Enterprise or Antepo--and those services can be pricey.

Price: Free

Best for... Running your e-mail

What it is: A downloadable e-mail server, similar to Microsoft (NASDAQ:MSFT) Exchange. Like Exchange, Zimbra offers shared calendars and contact management tools.

Why it's cool: Zimbra works with Windows, Mac OS, and Linux, giving network administrators plenty of flexibility. Zimbra lets you edit documents and spreadsheets even if you don't have a suite like Microsoft Office. You can use it to merge things like Yahoo Maps into your e-mail program.

Drawbacks: Synchronizing Zimbra's server software with a program like Outlook requires a paid version of the product. That's true for adding support for mobile devices like the BlackBerry, too.

Price: Free, but no support. Network editions cost $25 per user per year, minimum of 25 users (including unlimited e-mail support). An expanded business version costs $35 per user per year, minimum 25 users.

Best for... Replacing Microsoft Office

What it is: An alternative to Microsoft Office, including spreadsheets, word processing, and presentation software. ThinkFree works on the Web and you can use it without having to pay pricey licensing fees.

Why it's cool: ThinkFree may be a competitor, but it also works with Office (both the Windows and Mac versions). The company offers 1 gigabyte of online storage--free.

Drawbacks: The software lacks two of Office's key features--e-mail and database tools. Because it's hosted over the Internet, privacy could be an issue, though ThinkFree offers a server edition that lets businesses control their data.

Price: Free. The server edition, which allows you to store data on your downserver, costs $30 per user per year.