I paid a wee man to clean my oven just after Christmas, £65 and it looks like new. I did toy with the idea of giving it a once over before he got here, but in the end laziness over-ruled my pride.
2sp....what sort of oven have you got? I've got one that has double glass and there's muck between the two pains. It's really hard to get out and I'm scared I'd break. The other oven is single glass and very easy to clean.