I'm glad you've gotten into LPS collecting! To answer your questions:
I'm personally not into G2 LPS, though they appear to be really popular.
The value of G1 LPS sets varies dramatically depending on how rare the set is...a lot of the sets from 1995/1996 seem to be worth more, since the distribution for LPS was apparently not as widespread at that time.
I've never seen any guides to the new LPS, but there are a few sources for G1 LPS:
-
Tabby's List: this is an old site that is no longer updated, but it's super helpful.
-
Zuse's Guide: zuse has done an amazing job compiling an incredibly thorough guide!
-
LPS Collector: this one is my site:) Some of the images are fuzzy right now, and in addition to fixing that, I'm currently working on a new design that will have a visual ID guide, etc. (which should be up in a week, I hope!)
-
Kenner LPS Forum: lots of serious G1 collectors post here!
Anyway, welcome to the LPS collecting world!