Doug, its hard to sum up in a few word - or even if a few books! SQL Server (and Oracle) are a bit different from some databases (Access, maybe Foxpro) in that with programs like Access all the work is done on your computer - SQL Server runs on a different machine and is designed to handle many users at once.
As far as learning SQL, there are really two paths - you can be a Database Administrator (DBA) who maintains the software, tunes it, handles backup, etc, or you can be a developer who uses SQL Server as a place to store/access information. Lots of hybrids of those two paths out there. I'd suggest you search for DBA here on the site, you'll find some interesting articles and discussions.
Beyond that, I'd recommend you pick up a beginner SQL book and do some reading, see if it interests you.
Hope that helps.