Earlier today it had been assumed that Limera1n by Geohot would be released on October 11th, one day after the GreenPois0n jailbreak from the Chronic Dev-Team, However, in a strange twist the former is now live and ready for download.
We can already see by the number of tweets from @chronicdevteam that they do not seem too happy to be beaten with a jailbreak for iOS 4, which unlike GreenPois0n supports all models of the iPhone, iPod Touch, as well as the Apple iPad.
Limera1n is currently only available for Windows, which you can download by going to the official limera1n website. Mac and Linux versions will be coming soon.
Once you hit the download for windows link you will then have the choice to open or save a text.doc file, from there you will be given full instructions. Let us know how you got on.