1) I like Tux Magazine for general use type articles. Since I use Debian, I like the Ubuntu Guide (it's actually for Ubuntu linux, but I can usually figure out how to make it work on Debian). Sorry, I had a bunch more but I just realized I lost all my bookmarks with a HD fail last week. Oh well, you'll find some. I definitely like linuxquestions.org.
2) I'm sure you can, but I don't know how.
3) You can mount NTFS. Read only mounting is pretty safe. Write support is like playing Russian roulette. It's better to create a shared FAT32 partition to use files from both Linux and Windows.
4) I think it depends on the server setup, but I know Evolution is supposed to be the "Outlook" replacement. I set up my sister in law to use Mozilla Thunderbird at school using IMAP. My understanding is that IMAP leaves the messages on the server, and POP3 downloads them and usually erases them from the server. So if you want your messages from a webmail application at your friends house, you can get them with IMAP. But if you don't ever want access to them except from your laptop, POP3 works just as well.