iPhone 3GS 5.0.1 Firmware Download

I need to download the iPhone 3GS 5.0.1 Firmware and all the links that I have been to do not work. Does anyone here have this available for download? I am trying to jailbreak my phone using RedSnow for my MMS to work for Straight Talk service. The download for upgrade 5.1 does not work on the Apple site.