In this position, if you played Nc7+, you could capture the pawn on d5 giving you a pawn advantage. It would be a tough calculated battle, but I feel with correct play you could capitalize on the advantage.
Is this endgame drawn?

Nc7+ doesn't work, because he's in check. If he wasn't, that probably would lead to a win. If you could take out the pawn on d5, the queenside pawns would have an advantage you might be able to press for a win. Rybka evaluates this as +0.52, on another note.

Lots of chess programmes aren't great at endgames. Some don't even seem to realise the threat of pawn promotion!
I accepted the draw on the basis that blacks knight would be able to take my kingside pawns.