Asus P5G41T-M LX @3K
the mobo you suggested supports only DDr3 mem but OP has DDr2 mem - so he needs to get DDR3 mem with that mobo
@ OP - for OCing the cpu have you first need to invest in a decent cooler - even a CM Hyper TX3 will do just fine,
For the mobo get Gigabyte GA-G41M-Combo - supports boith DDr2 and DDr3 mem and price should be around ~2.5k - this combo of mobo and cpu cooler will be helpful to OC your cpu