Assuming your DSLR is at least 8 megapixels, I'd get at least a 1Gb card. I use Sandisk Extreme and Ultra cards. If you don't want to spend lots of money, I'd get the second-top speed card. For example, looking at the Ted's website, you can get the latest Sandisk Extreme IV in 2GB for $129.95 (that's currently half price, by the way!) whereas the Ultra II in 2GB is only $79.95 (currently this represents a 20% discount).
The Ultra II isn't as fast as the Extreme, but the camera probably can't even support the higher speed anyway.
See
http://www.teds.com.au/www/6/1001102...y/1001233.html
Cheers
Morton