Same problem except I seem to always hit the "n" in between words instead of the spacebar, once I can find the camera connection kit I'll hook up a spare USB keyboard.
That's the exact thing that in was doing when I first got the iPad, but I seemed to have overcome it... Now I keep hitting "q" instead of hitting "a".
I actually typed this post up to this sentence on the iPad in about 37 seconds with no issues, so I think I'm doing alright.
The only thing that trips me up sometimes is the auto-correction. I wish you could add custom words to the iPad dictionary or set it to replace certain misspelled words with others. Anyone else agree?