I installed facetime activator in my iphone4 4.1 and facetime appears evrytime i call. I deactivated it and now trying to activate it but not activating. What seems to be the problem? I need help now to activate facetime again, i tried to unistall and reinstall but nothing happened.

okay, first ... i need to ask you a question ...
Was the face time preinstalled in your iphone when you have bought it ??
if not, no problem =)
follow the following steps
1. Cydia.
2. Tap (Manage) then Tap (Sources).
3. At the right top corner, tap (Edit) then (Add) on the left side.
4. Add the following source- http://apps.iphoneislam .com
5. Tap (Add Source).
6. After you add the source hit (Done)
7. Now you're gonna find iPhoneIslam through your sources, tap it.
8. You'll find FaceIt-3GS, tap it then (Install) then tap (confirm)
9. After that, Tap on (Reboot)
10. Now, Go to Sittings --> Phone and you'll find FaceTime. Turn it On and make sure that you've previously saved your number in "My Number" filed that just above it and make sure that it's in the International form such as "+(country code)(Your Number without the first Zero)" eg. +151356345452452
11. Now wait from a minute to 10 minutes and it will be activated. If it's not activated after 10 minutes, give it some time again and Reset The Network Settings.

NOTE: This procedure was mainly to activate the FaceTime on iPhone 3GS. But i tried it on two Locked iPhone 4 firmwares 4.1 & 4.2.1 and it worked perfectly.

It's important to note that this can be VERY, VERY expensive for people. The facetime activation requires an SMS to be sent to an international number for most people who aren't using the phones in their destination country. Aside from that, certain networks block the activation response so your phone will continually send activation request SMSs to an international number and chew up your bill -- I would suggest investigating the SAM (Subscriber Artificial Module) solution that is available now -- it works some magic to allow standard activation through iTunes for users who would previously have had to hacktivate. This also resolves some GPS, FaceTime, Push Notificiation, and YouTube issues that have been longstanding due to the way hacktivation works.

sam won't by itself fix facetime. you still need to activate facetime via SMS. Apple is limiting SMS based activation to carriers where it has arranged a specific deal with.

Even a "commitment free/factory unlocked" iPhone will have problems activating facetime from a carrier that hasn't entered into an agreement with Apple relating to facetime.

However, Facetime will never be enabled without legitimate phone activation (which SAM enables for those using unlock)