Gordez :
i wasn't able to find those QVLs. though i see in ram specs which motherboards are they compatible with
(EDIT: nevermind i was able to find it!)
is there something i should be aware of while overclocking? and what is difference between motherboards. why would i get 120$ motherboard if 70$ one has same specs?
In short, you get what you pay for. The more expensive ones will have better electronic components and more features such as wifi, dual network ports, bigger heatsinks, sli, glowing lights ,etc., so you should consider your needs on top of price.
For overclocking, a good place to start is look at what type of VRM it has. Generally cheap motherboards start with 5 or 6 phase VRMs. While some of them can be used to achieve modest acceptable overclocks, the results won't be the greatest because as you increase clockspeed vdroop becomes a factor for failed overclocks. The better tuned mobos are better at achieving stable currents needed for high overclocks.
However generally you don't need that much overclock. Squeezing the last 0.2Ghz out of a CPU isn't going to make that much difference for most people's everyday gaming use. The primary reason for me to get a better board would be stability and hoping that it leads to longebity of all the components in the system.