There is a function called ( if I remember rightly ) GetSpellInfo. One of the items returned is the path to the spells texture icon. There is also I think GetSpellIcon or something similarly named just to get the texture. One I think is taken from the book and another is from the spellID or spellName itself.
Edit: Ah nope it was GetSpellTexture. Here are the two links to those functions on the wowwiki interface pages.
http://www.wowwiki.com/API_GetSpellTexture
http://www.wowwiki.com/API_GetSpellInfo
I use GetSpellInfo in my addons and can validate the existence in the spellbook by testing it against the SpellLink instead of the SpellID. The former will fail if you don't know the spell yet and the latter will give you the information. It is how I got the portal/teleport spells to display even if you had never learnt them yet.
This page has an example of reading through the spellbook to grab the spell information available there :
http://www.wowwiki.com/API_GetSpellName
But, as to a list nope, you would probably have to trawl through the wowhead database for that information and even then it may not tell you the texture path.