I got a mini USB hub from bestbuy for like $9.99...they had it onsale for like $5 last week. Anyway, its a 4 port splitter, and does not require an external powersupply.
edit: quick look on ebay shows this:
USB HUB
thats looks exactly the same as mine. And its going for under a buck right now ($6 shipping tho
). Do a search for "4 usb hub) and it will come up, along with a bunch of other auctions for the same thing.