I took my CK on 12-19-06 with results released 1-17-07, so it took 29 days. It usually takes less than that, but the holidays slowed it down. When did you take your test? Keep in mind, scores are released Wednesdays only!
Your estimate (3-4 weeks) is usually correct. Sometimes, scores are released in less than 3 weeks and, on rare occasions, more than 4 weeks. You should have your scores by mid-August.