I have had great success with the Ariadne I or II ZII network cards. You will need to search here, Amibay and eBay to find one. You shouldn't pay more then 100US for them.
They work great in the 2000 and I use the network card more for file transfers from my Mac desktop then for surfing, as its pretty lame.
But like they said, it may not look nice or be horribly slow to use iBrowse without an RTG card.
