<< should I have them sent to LSAC or directly to the schools? Is there a difference?>>
I didn't apply to many schools, but they all wanted the LORs to come from LSAC. I suppose if there were just no way to do it, you could always ask the admissions office if the recommenders could send LORs directly to the school, but that seems like way too much work for everybody.
The upside to sending them to LSAC is that recommendation letters usually aren't specific to the school you are applying to. As such, you send them once to LSAC, and getting them to each school is as easy as the click of a mouse.
<<2.) I keep hearing all this talk about an LSDAS GPA. Is there somewhere on the LSAC app that I would input my grades or is it just based on the transcript that I submit to LSAC?>>
They calculate it for you based on your transcripts.
<<3.) Is a resume typically submitted with an LSAC app, or is all of the information (professional/volunteer experience) inputted somewhere on the application itself?>>
I think there's a place to upload it. Most of the schools require you to fill out an application for admission that is separate from the stuff in LSAC. (You still submit it THROUGH LSAC, but it's the school's document, not LSAC's). You can put that information, there.
When you start putting your credentials into LSAC, the schools all have different criteria. They basically all want LSAT and transcripts. Some require LORs. Some want a personal statement. One of the schools wanted a resume, so I uploaded one.
When you start submitting your stuff to LSAC and start applying, it'll get a lot clearer. I think LSAC is a great service and worth every penny, especially if you're applying to a lot of schools.