I don't have any personal experience with the Belkin USB wifi adapters. What you need to do is go to
Belkins website and search for the model number of the adapter you are considering. Then see whether or not there are OS X drivers for it. Unfortunately there are very few wireless products with OS X drivers (because most recent Macs have wireless cards built-in, so there isn't much of a market). You could also check out
IOXperts which has commercial (i.e not free) OS X drivers for some otherwise unsupported wireless products. BTW, although many USA based eBay sellers dont want to ship overseas, some will, so you can always ask. A used original airport card would be the most convenient option (and it will definitely increase the resale value of your iBook--so you could reasonably consider it an investment rather than an expense.) Good luck.