hi friends i have one doud in my mind that if we exchange link with url which has PR less than my URL than my SERP will decreases?????????
No, your SERPs won't decrease for having any lower PR site link to yours...your SERPs WILL decrease when you link to a "bad neighbour". Not all PR 0 sites are bad neighbours.. Your SERPs can decrease if in the meantime your competition is building much stronger links