Is it possible? How do I go about editing code? I guess a local *AMP server is out of the question.
I think the iPad could be used quite happily for code editing (if you can cope with the keyboard and restricted applications).
I’ve got an app for my iPhone called FTP on the Go which literally lets me edit my site remotely, it’s awesome. 
iPad isn’t really the sort of device for development, it’s really aimed at end users who simply want to surf the web, email, browse photos/media etc.
That said, if you look through the App Store you’ll probably find plenty of editing apps, but it’s not like a conventional personal computer so running MAMP will probably be out of the question.