I am typing this on my iPad, in my lunch break at work, using my macbook pro which is sitting in my spare room at home.
I'm using Parallels Access. Remote Access tools aren't anything new, but Parallels access does a brilliant job of "appifying" the mac software so it runs easily on the iPad. It doesn't just share the screen, but it resizes it, and does other little bits of magic to make it feel iPadish.
It costs $80 a year, which wont be worth it for many. I am using a 6 month freebie trial i got for upgrading to parallels 9. So far, I am impressed.