Well there is Eagle:

http://www.gustavobarbieri.com.br/eagle/docs/eagle.html

which is a bit rough, but does work.

Or, you could write webapps for the browser which might run acceptably once the FF 3.0 Gecko engine is available on the tablets.

Otherwise, prepare to spend a lot of time learning Scratchbox and how to write programs that only run on the tablets (Hildon-specific). Sad, really.