Moments ago, kicked off by a hipstertastic soiree at the SXSW convention, the final build of Internet Explorer 9 was made publicly available. You can now download it from the Beauty of the Web site.
There are no significant changes between the RC and the final build; it's more of a spit-and-polish than anything else. Microsoft tells us that performance has been improved on low-end machines (with low-end graphics cards), but we can't confirm that yet. There's also a handy link from the Tracking Protection UI to the ready-made Tracking Protection Lists.
If you already have the Release Candidate or Beta versions installed, the RTW (release to world) build will be offered via Windows Update (presumably tomorrow morning). If you don't have the RC or Beta builds installed, you'll have to grab it manually.
Download Internet Explorer 9 for Windows Vista and 7
source: Internet Explorer 9 download