On my MB 2010 Lion and MBA 2011 Lion is an "old" free Version "NTFS-3G 2010.5.22" from Tuxera. Unfortunately it is a 32bit - Version. http://macntfs-3g.blogspot.com/2010/06/ntfs-3g-for-mac-os-x-2010522.html
(for free) Please use exact this Version!! No other version will work on Lion!
And you need to install MacFuse 2.1.9beta. http://code.google.com/p/macfuse/
For me it works fine, but it's not made for speed-lovers. (You get what you paid for.)
AND to format Your new HD/Stick in NTFS, you should use an WinPC. (Vista in my case)
For more speed you can download the all new 64bit super-duper extrafine "the only original" from Tuxera ($$$$) like Kappy wrote.
Hope this is usefull for you.
One more thing ;-)
What about encryption?
If you install TrueCrypt on your Mac. (and a Win-Version on PC)
You can create an TrueCrypt-drive on your Stick. If encrypted on MacOS it can r/w on Mac and Win. So you have not to deal with 32bit.