Just thought I'd put all of these together in one place and make it so people didn't have to wade through multiple threads/pages just to find the parts that work.

Listed below are the keys/remotes (standard or flip style) that we know can be programmed to the Mz3. For key purchases, if you provide your VIN to Jason he'll cut your key to your car before shipping. There are premade kits on onlinemazdaparts that combine the appropriate keys/remotes for your convenience. All prices include shipping.

Standard key/remote (non flip style):

-Mz3 transponder key ('04-'07): Part number F1Y1762GX. MSRP-$23.65, Website-$18.92
-Mz3 remote fob ('04-'06): Part number BN8P675RY. MSRP-$76.29, Website-$61.03
-Mz3 remote fob ('07): Part number BAN6675RY. MSRP-$141.05, Website-$117.84


Flip key; key portion: You need both a key portion, and a remote portion (see below for remotes)

-Mz5 flip key blank: Part number G2YA762GXA MSRP-$47.45, Website-$37.96

Flip key; remote fob: Pick the remote for your year model

-Mz6 flip remote fob ('06): Part number GP7A675RY MSPR-$46.35, Website-$37.08 works with '04-'06 models
-MX-5 flip remote fob ('05): Part number NE01675RYA MSRP-$186.20, Website-$148.96works with '04-'06 models
-Mazdaspeed3 flip remote fob ('07): Part number GP9C675RY MSRP-$111.71, Website-$89.37 works with mazdaspeed models only

Note: Currently there are NO flip key remotes that can be programmed with the US 2007 Mz3 computer. To use a flip key on a 2007 US 3 you need to replace the keyless entry module with that of a Canadian Mz3.

Some other key/remote related threads
How To: Programming a spare remote
How To: Programming a spare key
Flip Key Discussion
2007 Flip Key Information

Note: In order to program an extra key into your system yourself you need to have at least two working keys already. If you only have one then you need to go to the dealer to have them programmed in. You can program up to three remotes, but there is no requirement for preprogrammed remotes to program new ones.