Alayna,
With the Canon SD-1000, you'll only be saving JPEG images so that will simplify things to some extent. I'd suggest taking 3-4 SD cards, perhaps 4GB each. That will provide lots of capacity.
It's a good idea to back up your photos in some way, and the others have suggested several ways this can be accomplished.
I'm not a big fan of using an IPod Classic (which has a hard drive) for photo backup, as I've had an unfortunate experience with that method (a bad experience which involved the loss of some great pictures).
The most reliable methods for backup would either be a Netbook or a dedicated photo storage device, such as those manufactured by Epson. If you'd prefer not to use either of those methods, you could always have DVD's burned at local computer or photo shops in whatever cities you visit.
Good luck and happy travels!