Well actually, in Tome and Blood (page 12) it does say what happens to a familiar of a dead master. Sure it's 3.0, but if I remember correctly, previous rules apply unless updated.

So far, I’m avoiding most 3.0 material, because some un-updated material can cause real problems when used wantonly in 3.5. In this case, though, I was mostly pointing out that its lack of appearance in Complete Arcane (which, in most cases, is the update of Tome and Blood) or even the PHB is pretty noticable.