while probably not the best platform to do web development on, an ipad can be used to create code for your website.
I use my ipad mini (in emergencies) to fix code if needs be.
there are lots of apps out there, but the ones I choose to help me are:
issh it lets you log on via ssh to servers. it also does X forwarding, so I can log in to my workstation in the office if needs be.
Koder is like a mini IDE for an ipad. it supports ftp / sftp / dropbox / webdav / local development. and it has firebug built in to it
diet coda is also a paid app, but it looks to try to emulate coda, but on an ipad!
and you will always need an editor:
Vim has an ios port too!