How do I connect my new Jornada 548 to the Internet and, once connected, access AOL (not AOL mail)?
AOL provides AOL Instant Messenger in Windows CE format. That provides you with real-time chat capabilities. As for directly accessing the service for dial-up, AOL doesn't list any versions of its software for Windows CE.
Your best bet is trying a new ISP and using AOL's Web tools to connect to your account.