Actually, if anything there are MORE features available in a Server OS. In general they can do anything the Pro version can and often far more. Be a DNS, WINS, DHCP, FILESERVER (for over 10 simultaneous users), Windows Media Streaming server, Domain Controller, support more RAM, support for more processors, ETC. Its not restricted at all. In fact, it will probably ship with Media Player 9 built in.
I wouldn't worry about what it can do, but I wouldn't post that you are getting a copy of Windows 2003 server from your brother, as I am pretty sure its not legit to run it if you aren't using it for School purposes (as in a class). Do what you want to just don't give us too much detail.
THanks.