10.3 is fairly recent, though not the absolute latest...10.3 is a mature version of OS X, and AOL should work just fine...be sure to run 'Software Update' in the system preferences...it should come up automatically every now and then, but it's good to check it yourself to keep things up-to-date, especially if you are on dial-in...also, if there is an apple store near you, go in and ask them if they have the updates on disc - they are going to take a looong time via dial-in...
...as far as Mac sites go,
www.macsurfer.com is a great one-stop site for all the Mac info you are likely to need, be it news, tech info, gaming, iPod, rumors, etc...the site itself provides links and headlines from many different Mac-centric web sites elsewhere...it's a great resource...also, don't be bashful about picking up a copy of 'Macs for Dummies', 'The Missing Manual' or a similar type of noobie book - they are quite good references, even for more experienced users...
ps - if you can, I highly recommend getting a broadband connection...unless they specifically state that the actual internet connection is not Mac compatible, it will work...I have Macs on both Cablevision's Optimum Online service and on DSL...it's worth the extra cost...