Help me overclock my 81GX

I have a Gigabyte GA-81Gx mobo I would like to overclock, it seems to be pretty OC friendly. I have never overclocked my computer before so I lack experience, but I have watched my brother do it many times so its not really new to me (if you know what i mean).
The motherboard came with EasyTune 4, it seems like its pretty easy to use, but would it be better to just OC through the bios? or does it not make a difference?
thanks in advance

bios is your friend. what are your current specs?

hey thanks for the welcome
right now i have
P4 2.2
81GX mobo
did have 786Mb pc 2700 (max supported on mobo is PC2100) my brother took out his 512 so i only have 256 right now
ATI 9800 pro AIW (also bottlenecked by mobo at 4x )
antec psu 330w (came with case)
all packed into an antec case

alright I overclocked using the bios, heres the process I used to test my results:
OC in bios, let windows startup, run easytune4(only for monitoring purposes), run diablo2 in window (to keep cpu at 100%), run winamp and play songs(to check sound continuity), reboot and start over

heres what happened:
OC sys bus up to 105mhz (100 default), but windows would freeze up either during loading or when it was starting my programs that startup when windows does.
I figured it was freezing because there was not enough power (is this right? remember my psu is 330W) so I unplugged my slave HD which seemed to solve the problem.
After that was solved, I stepped the sys bus up and once it got to 107 my sound (onboard) will skip. Right now its running with no problems at 106 (running 45 deg. C with cpu at 100%) with the slave HD unplugged.
so my questions are:
to allow me to OC over 106 with no problems, I have to go in the bios and up the cpu voltage right?
and in order for me to have my slave HD plugged in while OC Im gonna need a new psu or unplug something else (maybe fans) right?