This skill uses a mechanic that I developed some time back for inclusion in the Skirmisher Publishing sourcebook Experts. I think it is rather clever, in that it allows significant skill advancement to have a moderate effect on divination types of spells. This impact is dependent, of course, on a skill check. I have written up several of these but probably just need to combine them all into a single "Knowledge (Divination)" that lists several variations (e.g., cartomancy, necromancy, seromancy). 

Special: If a character has at least 5 ranks in Knowledge (Necromancy) and succeeds at a DC 25 skill check immediately prior to casting a divination spell, he is treated as if he were two levels higher for purposes of that casting. This cannot be used in conjunction with the benefit bestowed by another type of Knowledge (e.g., Numerology); only one or another can be used. 

Synergy: If a character has 5 or more ranks in Knowledge (Necromancy), he is able to avail himself of the senses of any undead that he commands as the result of a successful rebuking attempt (e.g., see through their eyes).