Most of the networking options for A500's (a few sidecars released back in the day) are rarer than hen's teeth. You could use the side expansion port with a Zorro II card, or maybe Plipbox? Don't know much about it but here's a link to get you started:
http://lallafa.de/blog/amiga-projects/plipbox/
Thanks for the link: I didn't know.
It's a cool project!
Maybe is not that fast, but it's very elegant for machines like A500.
