There's no complete list of accommodation around Fort William. The tourist office only keeps 'registered' addresses and on my last visit they drew a complete blank as all beds were taken. There are plenty of 'unregistered' B&Bs, but you have to do your own hoof-work and tramp around town looking for them. I got lucky last time, since I was just about to give up and go and find a bivvy for the night, when I found the last B&B with a bed available!