Flickr is free up to 100 MB of bandwidth a month... it's actually run by Yahoo now, which is probably why the Yahoo photoalbums are being discontinued (just my guess).

I've used it for a few months now, but ended up having TONS of travel photos, so I "upgraded" to the unlimited version and paid for a year of service.

I think it's the best amature photo-hosting site, personally... I don't like how people who want to view your photos have to log in to the other services to see them (ie: snapfish, kodak). And I like all of the community stuff Flickr has (and the automatic blog posting!).