There are many applications available on AppStore that require firmware 3.1.3 installed on your iPhone. However if you don’t want to upgrade the iphone firmware, here is a simple solution for this problem.
Finally it has been disclosed by Charlie Kindel, Microsoft Partner Group Program Manager for the Windows Phone Application Platform & Developer Experience, that the existing applications of Windows Mobile will not run on newly launched mobile OS by Microsoft.
Pushme.to is a beautiful application that allows you to send instant messages and images to your iPhone and iPod friends. The unique feature of this applications is that you don’t need to have an iPhone / iPod / email / registration etc to send messages.
HootSuite is very popular twitter client among social enthusiasts esp bloggers. They have released an app for android phones (like Google Nexus One) and this app is similar to iPhone HootSuite App in functionality.