windows 2003 SBS group policy

hello,
we have windows sbs 2003 domain, all clients are windows xp pro SP2

i wish to make some changes in the domain,
1) open windows firewall for all users

2) allow OS updates for all users ( presently we need to login as the administrator)

3) make login to the domain fast,

4) allow remote login for all users on win XP ( though checking on the allow remote connections OS dosent allow remote logins )

5) change date time format for all users at the same time

i want to do all these changes through group policy, kindly guide me in this
thanks

AD