Session Transfer Help

[Funkle]

Hey guys I've never transfered pro tools files/sessions before and am in need of some help. I just recieved my new Macbook Pro and finished installing pro tools le 8 onto it. Now im wanting to transfer all of my pro tools sessions from my desktop PC to my external hardrive - the Seagate Freeagent usb 2.0 500gb (As seen here: http://www.amazon.com/Seagate-FreeAg.../dp/B000ND75C0). I believe all my pro tools related files are installed to my PC's internal hardrive(s). What files/folders will i need to copy to the external hardrive? Will it matter that the hardrive has about 257GB used on it with mainly media files (movies and music)? Should I be able to connect the hardrive and open the session files i want through pro tools immediately or is there anything id have to do first? Also, would it be better to just move all the session files onto the mac's hardrive? Or should i invest in a firewire external? Sorry for all the questions but im in need of answers quickly as im flying home in a few days and wont have access to my session files if i dont get them transfered NOW. If anyone can help me out id really appreciate it!