In the Phoenix area, the best places I've found so far are Scottsdale Sports Complex and the fields in and around Riverview Park in Mesa. Sometimes you can find decent wind at Chaparral Park. Caveat - I live on the east side, and haven't really explored elsewhere.
The sports fields around Salt River Fields are great, but I've gotten conflicting information on whether they allow kites or not. Some staffers will kick you off the fields, while others will enjoy watching you fly. There are no posted signs stating one way or the other that I've seen.
In general, the wind here is really hit or miss, and it's hardly ever smooth. Right now we've gone nearly three weeks without any wind worth mentioning, other than maybe a couple of hours during my workdays (of course).
Anyone else have any other good places? I could use some new suggestions as well!