How to implement Reachability for iphone application

I am developing an iphone application which uses internet.So in order to handle the 开发者_如何学运维network connection errors i would like to use reachability,but from apple site api reference it states that build and runtime requires iOS4 but i am developing application for iphone 2g which only supports upto iphone os 3.1.3.So any one could help me in implementing the reachabilty class.

Thanks in advance for all stackoverflow masters........

Check out the modified Reachability in ASIHTTPRequest, which includes support for older iOS versions.