Evite offers send to phone event details that result in a text message. Now that message will include a telephone number for speech-enabled turn-by-turn directions. The user calls (or clicks to call) the number, offers a start address and then receives directions via text. The destination is already identified by the system so the user doesn't have to repeat or specify it.
Here's the sequence:



It's a very useful extension of the Evite send to phone service. Dial Directions provides a similar "voice-activated directions" capability for IAC sister company Ask.com's mobile search.
Here's the Dial Directions' release and a demo video.