FreeBsd 8.0 : Just for Gurus! Trunk/Etherchannel mode

Hi Buddies!
I need to do a new kind of setting in FreeBSD (i'm a newbie using this OS).

Interface 1 y 2 in Trunk/Etherchannel mode
IP-> xx.xx.xx.xx
netmask-> 255.255.255.0

Anybody can help me with a step by step Guide?.

THANKS A MILLION!!!

Do you mean trunking as in transfers all VLANs, or do you mean trunking as in "commonly used, though false term for link aggregation"? For the later, there's a section in the FreeBSD handbook on how to use man lagg (FreeBSD)