Dial Directions has introduced a service that gives travelers one less thing to worry about while on the go.

Users just dial DIR-ECT-IONS from any mobile phone, speak their starting location and destination and the service instantly sends turn-by-turn driving directions by text message.

"We are all about giving directions to mobile phone users," said Tuyen Ho, head of marketing at Dial Directions, San Francisco. "The service is very simple. There are no registrations or service charges. The service is practical and useful for everyday people."

The free Dial Directions service for directions by phone call is available nationwide to all cities in the continental United States. No Web plan or GPS is needed.

"We will be serving up a text ad that appears at the bottom of the texted directions," Ms. Ho said. "With our mobile technology and the fact that the service is location-based we use geo-data and time of day to send targeted and relevant ads."

Dial Directions is working with text message service provider 4info to sell ad space.

San Mateo, CA-based 4info claims to deliver millions of real-time SMS answers and entertainment messages both as a response to a search query or as an alert on subjects such as sports scores, weather updates, stock quotes and celebrity gossip. 4info's services work on any mobile phone for free.

Companies also partner with 4info to connect with their mobile audiences and deliver free, ad-supported SMS content. 4info's SMS ad-serving technology and targeted advertising programs are designed to give businesses the ability sell targeted ad space.

Dial Directions will soon be introducing a new feature called Meet Me, letting callers create social events, invite friends and send directions.

"Right now we are focused on making sure people are comfortable with the service," Ms. Ho said.