"via transit" in siri (using 3rd party routing apps without hacks or address book tricks)
I had found this on a apple web blog, tested it and was surprised, and figured i would share. After downloading google maps, ask your phone to give you directions to an address "via transit"
"take me to 4 rockerfeller plaza, manhattan via transit"
This tell's siri to use a transit based app, bringing up this screen:
Nice touch, and it could be the first hints of opening up Siri slightly more for 3rd parties. To bad my favorite actual subway app (NextStop) isn't included!