Over the years I have been asked this question many times. Usually my first response is - "it all depends what you already have in your tool box". But assuming you do not have much in your tool box, here is a list of what special tools you could need.
Cam block fixing screws
TDC gauge holder
Cam belt tensioner tool
Exhaust pulley tool
Inlet pulley tool
Obvousily you could try changing the cam belt without any special tools (I know people that do this) but I find that the more tools you have the easier the job and there is less risk of damaging your engine
Also I can not recommend enough downloading or buying a copy of the factory manual and having a good read of the cambelt changing section before you start taking the engine apart. If you have not already got one have a look in the download section of the main website as you will find one there (if I have found time to scan one in!).