is there a notepad app that is capable of 2-way syncing, preferrably over the air?
Second Evernote. And it's good for more than just text, it also handles audio notes, snapshots and other files. Plus there are windows, mac, winmo, blackberry, iphone clients as well as a pretty good web client (oh, and of course an android client).
Actually as I re-read the OP's request, I think the only one of the apps mentioned here that provides for true 2-way synch is gDocs. The others allow the user to upload notes to a site where they can be stored but only gDocs allows for editing and synchronization on both sides.
Evernote, for example, does not allow for downloading from one's Evernote account, only adding material to that account.
NoteEverything is similar (though it provides for some other features missing from Evernote.)