You can use 51. For controlling fan and light you can use optoisolated triac MOC3021 motorola which has a limited current capacity but which can be connected to other triacs. Details are in the datasheet. The device is available. For intensity control you will have to make a zero crossing (ZC) detector. The triac can be fired after the ZC for intensity control. For more details contact at jayantskathe@rediffmail.com or write message for jayant in sub at ertlbom@bom5.vsnl.net.in
regards

jayant