Just to clarify,
3.1 (7C144) was released for all three generations of iPhone.
3.1.1 (7C145) was released for all three generations of iPod touch.
You can download them directly from http://www.felixbruns.de/iPod/firmware/ (which basically parses the http://itunes.com/version XML feed).
iClarified stated that the BenM tethering hack was disabled back during the second beta of 3.1, so it's almost guaranteed that it's disabled in the final release.
3.1 beta 2 did fix the high-pitch noise issue that occured in many iPhone 3GS during recording of video and voice memos, so I'm sure it also remained fixed in the final release.
3.1 (7C144) was released for all three generations of iPhone.
3.1.1 (7C145) was released for all three generations of iPod touch.
You can download them directly from http://www.felixbruns.de/iPod/firmware/ (which basically parses the http://itunes.com/version XML feed).
iClarified stated that the BenM tethering hack was disabled back during the second beta of 3.1, so it's almost guaranteed that it's disabled in the final release.
3.1 beta 2 did fix the high-pitch noise issue that occured in many iPhone 3GS during recording of video and voice memos, so I'm sure it also remained fixed in the final release.