hosting is done right through the game. At the multiplayer screen choose Host instead of join. configure the options (server name, game type, select the starting map, number of players, ect) then click Start.
To host though you have to open up UDP port 17479 in any routers or firewalls you have.
For a server manager, one that lets you easily manage bans, map lists, display automessages, get anaconda (
http://condascode.com ). In the forums there is a tutorial on how to set that up and run it.
IcI