So I've been looking for a spell of any sort that fortifies a skill. I've been scrutinizing the UESP to no avail and I've just about given up. Anyone know where I can find one of these spells? I know its possible cause I've done it on a past character but I can't remember where he got it from

Find a Doomstone with a Fortify Skill component. I remember the Atronach Doomstone having a Fortify Intelligence component.

You can't buy such a spell, but there are several ways to get the effect (including what D-11) said.

In the notes section of this link, the other ways are detailed: http://www.uesp.net/wiki/Oblivion:Fortify_Skill