Fairly easy. There are 2 bolts that hold it in. 1 is acessable from the top of the engine which goes through the gearbox aswell and the second is acessable from under the car. The - is held on the back of the starter with an 8mm nut and the + is held on by either an 10mm or 13mm nut. When you fit the new one on, attach the power suply on before you bolt it into the gearbox, i find this to be easiest.
Kind Regards
Tristan Hanwell, April 2006