hotmail should be one of the default listings when setting up your mail accounts. so just open up the Mail app on the phone and hit Add/New Account. once you do that just enter your hotmail email and password and follow the prompts.
it should populate all the POP3 stuff you need automatically. if not, you can use pop3.live.com for the incoming server and smtp.live.com for the outgoing server.
you can also check out page 105 of the manual http://support.t-mobile.com/docs/DOC-1952
I suggest adding it as an Exchange account, that way your folders will sync.
Go to menu, Accounts & sync and then Add account. Choose Exchange ActiveSync.
After entering your email and password choose Manual setup:
Server address: m.hotmail.com
Username: "your email address"
edit: Check SSL connection