Re: Passing on of knowledge of spells...
Prestige classes can function as any class. They basically are like the old fashioned Bard class, and what I think I used to call Compound Classes. Basically being a class that has 'Prerequisites' for entering into it.
So what you would need to design, would be a Class Feature, which would be unique to the Prestige class. Actually, it would seem that what you are actually inventing is a form of metamagic feat (or set of them) that would have requirements tying them to the prestige class.
I'm trying to consider what you could use the skill to help with. I guess, actually, there are a variety of options on what you might be able to do. A couple that come to mind right away include, raising the effective caster level of the indicated spell. Another option would be increasing the DC, of the save, of the indicated spell higher than normal. Another thing I know is sometimes desired is that ability to have a bonus to penetrate spell resistance effect.
I can see each of those being a potential option for something like that.
Perhaps, for instance, making an appropriate craft roll, and paying some cost similar to a scroll or such, would allow you to make a material component with a particular effectiveness recorded. If using that prepared material component to cast the spell, there would be some process to compare the crafted object against the target, and if greater, affects the spell in some designated way.
Things I can think of... Result of Craft Roll must exceed: WILL, REFLEX, FORT save DCs, or CMB( Combat Maneuver Defence) for some examples. Not sure I have perfect ideas at the moment for them all though. But I could easily see using such a material component, being able to say improve the DC of the spell by a +2 (which would be significant) thinking of it as sort of being similar to a 'assist other' on the spell casting. A similar bonus of some sort to affect Spell Resistance Penetration also seems reasonable. These material components however would probably have to be prepared for a specific function (boost DC, or boost penetration) Actually, crafting special components could each be a different meta-magic feat. The prestige class would pick them up in a specific order, or you could allow them to pick one up per level or x/levels.