Gene function through sequence homology

Hi
I'm not entirely sure that this is the appropriate forum for this question, but I really need some help with this, so here goes.
So I've cobbled together a list of genes from Leptospria putatively involved in virulence. I need to produce a hypothesis on possible function through sequence homology. I'm looking at doing this bioinformatically, since the only resource I have right now is a computer. Despite a familiarity with bioinformatical tools, I have no idea how to go about this. Can someone give me some ideas or point me to a resource ( guides etc. ) that would help me with this ?