When many people think of instant messaging (IM), they think of teenagers pounding away on the keyboard and chatting throughout the night with friends. But IM has staked its place out in the business world, too. Case in point: According to the Radicati Group, the enterprise IM market is expected to reach $123 million in 2006 and grow to $282 million by 2010.

That said, free public IM programs still dominate both inside and outside the office. But they weren't necessarily designed with businesses with in mind. Small business leader need to be concerned that employees who use free IM clients can unknowingly -- or purposely -- send company secrets out over the unsecured  Internet without a trace. They could accidentally catch a virus or let a worm make its way from an IM attachment to the company’s network. Or employees could cause their firms legal liability due to the IM activities, such as having chats that violate company policy -- or the law.

Still, IM is growing up. There are now a number of programs or gateway products that allow businesses to better clamp down on IM to improve security, control content and manage and retain IM records. Here are three enterprise IM technologies and what experts have to say about their benefits:

WebEx AIM Pro Business Edition

Cost: Free download; subscription for premium services

Features: AOL released this free business-minded IM program in 2006. WebEx AIM Pro is free, encrypts messages between AIM Pro users, and allows users to import their public AIM buddy list and Microsoft Outlook calendars. “It’s pretty valuable,” says Chris Hazelton, IDC senior analyst, small and medium business markets,. The program also allows users to share documents, edit them via an IM chat, and do voice conferencing, as well. Businesses can use the program to monitor, log and archive text, voice and video IMs. It allows secure messaging with “AOL federated partners” such as Microsoft Live Communications Server (LCS) and IBM Lotus Sametime. WebEx plans to charge an additional fee per user for multi-party IM conferences in the near future. AIM Pro Professional Edition, on the other hand, is free and doesn’t include the archiving features, for instance, and requires a WebEx account to host voice or video IM conferences.

IBM Lotus Sametime

Cost: $55 per user, $475 for IBM Lotus Web Conferencing Concurrent User License, although prices can vary.

Features: As a secure end-to-end enterprise IM, Sametime Version 7.5 includes integration with Voice over Internet Protocol (VoIP) and about 150 new functions developed by partners. With Sametime, users can imbed 3D models in an IM, which Matthew Brown, a senior analyst for Forrester Research  says, “R&D organizations are very excited about.” Sametime allows users within an organization to see each other’s physical location, phone availability, a detailed company-directory like profile, or the recent e-mails a person sent you when they ping you with an IM so you can more quickly get up to speed about their needs. Users can search for an internal expert or start a discussion forum across the Sametime network. It also allows connectivity with public IM programs by AOL, Yahoo and Google.

Microsoft Live Communications Server (LCS)

Cost: $31 per user, $787 per server

Features: With LCS, Brown says Microsoft is going for a “unified communications strategy.” LCS allows users to collaborate via IM using other Microsoft products and from within Windows SharePoint Services and SharePoint Portal Server sites. Users can initiate phone calls from the program, too. It allows users to securely IM users of free IM programs such as MSN, AOL and Yahoo, and provides logging and archiving tools for regulatory compliance. LCS has a remote user option so employees can still IM securely when they are not on the company’s network. Like IBM Sametime, Hazelton says Microsoft LCS “is pretty expensive but it can be bundled with Exchange.”

If enterprise IM programs are not the right fit, businesses can still add a layer of security to the free public IM programs with gateway products such as FaceTime or IMLogic or by using a hosted enterprise IM service by companies including Omnipod or Akeni. No matter which enterprise IM program a small to medium business chooses, Brown says: “A lot of these IM technologies are starting to converge across all communications technologies. IM is going to make the way we interact and tight-loop collaboration more seamless.”