Good news for iPhone users. A new jailbreak tweak has been released in Cydia using which you will never miss to reply to all those SMS messages those are flagged read on your iPhone. The name of this tweak is iReply. After you have installed this tweak on your jailbroken iPhone it will provide you pop up reminder informing that your message is still unread and you have not replied it yet. You can manage incoming SMS by creating black lists and white lists. This tweak comes with number of settings using which you can define a message as important by simply adjusting various parameters.
You can download iReply from Cydia under BigBoss repository. It costs $1.49 USD. You should note that you will need to have a jailbroken iPhone to install this tweak. If you don’t have jailbroken iPhone then you can follow the step by step instructions posted here to jailbreak your iPhone on iOS 4.2.1 with Redsn0w.