From the press release:
A Portland Dadnab user sends an SMS text messages from a mobile phone to firstname.lastname@example.org. In the message, the user specifies an origin, destination, and an optional departure or arrival time. The service replies with step-by-step instructions for reaching the desired destination by light rail, bus, or streetcar.
Technology savvy Portland transit riders are well provided for; TriMet’s website, 238-RIDE, Google Transit, and NextBus also provide various transit information services. And local transportation blog Portland Transport provides a few useful transit tools.