My word, that was quick, I blinked and there were two pages of mail!

Head gasket - not the easiest job in the world but well worth doing, your engine should be good for at least another 150k when done. Someone is doing gaskets on ebay for about £12.50, but I wouldn't use one, get a steel laminated type, I got mine from Citroen and it was about £60.00 but I think they are available elswhere now, they look almost indestructable, the green one had covered over 75k without problems before Christine piled it up - got a good secondhand one if you want it.

The job is labourious rather than difficult, so much ancilliary equipment has to be removed to get at the head, possibly the best route is to follow the Haynes instructions apart from the bit that says you cant do it with the engine in the car, and take photo's at each stage so you know where everything goes back, I still have a box of bits left over from mine - mainly brackets

If you decide to do it I'm sure some of us can give you step by step instructions