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........

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