@sim085:
I have an A500+ that I can use to browse the web. The best way to upgrade your A500+ is, as you already guessed:
- an accelerator
- more RAM
- a harddisk
Often an accelerator will already offer you more RAM. You could try and do it without a harddisk and without an accelerator (I know, I did, just to see if it would work), but it will be slow as hell.
To get online you should indeed use Kickstart 3.x, because I think iBrowse requires it. Install AmiTCP (the TCP/IP stack). If you're on dialup a modem will work, but if you have broadband the easiest way is to hook up a null-modem cable between your A500's serial port and a PC or Mac and use a PPP connection. PPP is a pain to setup properly in Windows, but really easy if you use Linux or Mac OS X.
There are Ethernet solutions for the A500 (I have a Hydranet), but they use BNC connectors, so they're a pain to set up and also very hard to find.
Good luck with your setup!