I'll add my welcome to the thread as well :-)
Welcome to Amiga.org :-D
The A500 is a great machine, I still have mine, and the majority of software I have is OCS games, like Lemmings :lol:
As far as going online with an Amiga 500.....you're braver than I am :-P You should be able to get text browsing (ALynx, I believe) working well on there, and TCP/IP connection with your PC to share files should be alright, but you'll need a hard drive (unless ALynx works from disk :-?), at least 2mb of ram, and probably something more recent than Workbench 1.3 - I don't know if there's software for 1.3, or whether you'll need 2.0
All in all, it's a fairly ambitious project :-) I haven't tried it on my A1200 yet, but I'd say anything but text browsing would be fairly painful. Give it a go though, and let us know how it goes :-D