Get your self a suede brush (only a couple of quid from a shoe shop) and a tin of KIWI suede cleaner (red spray tin next to the boot polish, again only a couple of quid). Spray it on, work in with the brush and it will come up like new. I've done this on the dr saddle I bought a few weeks ago. The seat was soooo scabby and disgustingly dirty, and after using that almost looks new again. Just need to go over it again and get all the edges done as I ran out of spray first time!
ETA never use soap, water or anything like that on it, it will permenantly damage the suede.