Hi there,
as DM has said, the best way to go about overclocking a system is doing so through BIOS. This gives you total control over teh parameters being set and also allows for the overclock to be there from the moment you start your PC.
You don't say which revision your motherboard is but looking through the various revisions and their BIOS I think it must be the rev 2.0. The first thing I would do is update the BIOS to the FF version using QFlash. I wouldn't do this in one step though and would recommend going to FC first and then updating again to the FF. There are several updates that should help with your system and also some updates for the CPU Microcode.
Once you have updated the BIOS and have things running at stock go into BIOS and make a note of the default settings. You will find this invaluable when you start making changes especially as, at some point, the system is bound to fall over and it is easy to forget what changes you have made. It's a good idea to note the changes you make as you go along for the same reason.
With the Phenom ii 945 processor overclocking can be pretty easy. First make sure you have a good cooler as the stock AMD one won't allow you to get very far. In BIOS you need to disable the Core Boost, CoolNQuiet, Thermal Control and other features of a similar nature. Once you have done that you can start to adjust the CPU Ratio under the MIT section of BIOS.
First you need to set it from AUTO to Manual. When you do this it will give you a list of available multipliers X14, X15, X16, etc. If you are lucky they might be in smaller steps such as X15.5, X16, X16.5.
The base clock for the 945 is 3000MHz (if I remember correctly) and this equates to X15 on the multiplier. You need to increase the multiplier to the speed you are looking for but do not do this in one giant leap. If you want to overclock to 3600MHz (X18) then do so in small steps and check the system for stability before increasing the multiplier again. Continue this process of increase multiplier, test until the system crashes. This will either be a BSOD when loading or in Windows or a failure to POST/BOOT with an overclock warning.
Clear CMOS, go back into BIOS and reset things to the last know settings (you should find this easy if you have kept the notes I mentioned before) and this will give you the maximum overclock at default voltage and other settings. This may be all you want or need and you can stop at this stage.
If, however you want to try and increase the speed further you will then need to look at increasing voltages to the CPU and possibly other parts of the motherboard. Remember that increasing the voltage through a component will increase the heat being produced, hence the need for good cooling on the CPU and throughout the system. When increasing the CPU Voltage, care should again been taken not to make large adjustments. This stage of overclocking can be time consuming and you may find that you are having to reset CMOS on a regular basis to get things stable.
Another area to consider is the NorthBridge Frequency. This will most probably be at 2000MHz (x2 which gives 4000MHz) and this may need to be increased along with the increase in CPU speed.
Sadly, there are no hard and fast rules for any of this, as each PC build will have slightly different components, which is why overclocking is called an art not a science. What works on your friend's PC will almost definitely not work on your own, so it is really a case of trial and error until you are happy with the speed and stability of your own rig.
Make sure you use good monitoring software to keep an eye on CPU and System Temps and voltages. HW Monitor, CPU-Z, CoreTemp are usually pretty reliable and are the ones that I favour. Although I am talking about the 1090T CPU in this thread:
http://forum.giga-byte.co.uk/index.php/topic,3637.0.html you might find some useful pointers in it.
If you have any specific questions then post back and I'm sure someone will point you in the right direction
