On: WWDC sold out in ten hours.

[wallflower]

I've only heard good things about their Austin edition.

WHEN: September 11-14, 2011 WHERE: Denver, CO

http://www.360idev.com/

For Mac:

http://nsconference.com/

Props for NSConf:

http://mattgemmell.com/2009/05/01/nsconference-2009

[zdw → wallflower]

NSConference USA is merging with MacTech Conference:

http://www.mactech.com/conference/nsconference

Last year's conference was fantastic. Has IT and Dev tracks. Highly recommended.