I managed to get in touch with someone who worked in Google and they gave me a recommendation. Staff get a bonus if someone they recommend gets hired so if you can find someone who works there it shouldn't be too hard to convinve them to recommend you!
That got me a phone interview, which didn't go very well to be honest. I think good interviews flow like conversations whereas I felt like a robot giving plastic, pre-prepared answers and waiting for her to ask the next question. Looking back, I suppose I wasn't really enthuhsiastic about the job and I think that came across. Obviously, I didn't get the position!
Good luck with your on-sites, sorry I can't be more help. Have you looked at http://www.glassdoor.com?
GPA = Grade Point Average
It's basically just a way of averaging all your grades down to one number. I'm not sure how the figures translate exactly but you get something like 4 for an A, 3.5 for a B+, 3.25 for a B and so on.
I'm open to correction on this but I think it's an American thing that has only been adopted by Irish institutions fairly recently, so if you went to college some years ago it may not have applied.
So far, Google are the only employers I've come across that have asked for it.
I don't know anyone who works there though. I applied for another job in google and never heard back either for that position. I'm from a business/IT background so thought either job I applied for were suitable but obviously I wasn't a suitable candidate.
Thanks for the heads up and info Undoable.