If any has a blocked Iphone 4, contact 55502185 to unblock it:

SIM Interposer Can Unlock iPhone 4, iOS 4.3/ 4.2.1 On 2.10.04/ 3.10.01 Baseband, Albeit Legally Questionable

a new unlocking method for iPhone 4 users who are stuck on iOS 4.2.1, with 2.10.04 or 3.10.01 baseband.
It basically works by forcing the activation of the baseband using the emergency dialer, and it is also vulnerable up to iOS 4.3.