Strange keyboard behavior - odd characters

I am also having strange laptop keyboard behavior, but a little different than inserting odd characters.

While I'm inputting text, the cursor may jump back to the beginning of a text field or to the middle of a sentence and resume, resulting in a jumble of letters. Sometimes the cursor jumps multiple lines or letters ahead. When I try entering three of the same letters, it will only enter two, unless I insert the cursor manually. And all of this is intermittent.

Has my keyboard gone wacko? I've tried looking for possible keyboard viruses in Google, but nothing seems to match the symptoms. Also, the space bar under the track pad seems a little tight—doesn't always fell like it clicks when I press it.

Any ideas?

I have the same problem as beeweb. I think it's a different problem from the op, so maybe we should open a new thread.
While typing, the cursor often jumps ahead or backward sometimes highlighting the text already entered (and deleting it as the next character is typed)

I definitely keep my hands away from the trackpad as I type.

I repaired permissions and there was a huge amount of repairs for Airport including some that said "keyedinput" (that may be a red herring)

The problem is intermittent so it's difficult to eliminate variables.
Though I tried typing with Airport turned off and didn't encounter any problems.