Another vote for the Edirol R-09. It doesn't come that cheap but it is self contained and the results are excellent.

I tried other solutions, documented in other threads, which worked quite well but involved a fair amount of setting up. With a card and batteries inserted into the Edirol in advance it is litterally a case of pointing the built in Mics in the general direction of what you want to record, two clicks and you're recording. There are lots of options and settings, but these are extra enhancements. Although worth knowing about and considering, basic recording can be accomplished very quickly and easily.