Yep. I like that feature on my Iphone4 too. The ability to block unwanted calls permanently. So Cool!!
Also works miracles for those annoying family memebers too!!
Got a telemarketing call from this number for trip to Florida. Tried very hard to sell me trip for four people. I told them I had 7 kids and the put me on hold to check that it was Okay to have that many people on the trip. Then they hung up. I don't think they'll call back.