The Internet telephony startup Ribbit is expected to announce Tuesday that one of its initial flagship projects -- an integration with Salesforce -- is now generally available.

The service merges telephony with Salesforce's on-demand CRM (customer relationship management) software in a number of ways.

Users can push voicemail messages from their cell phones into Salesforce, attaching them to a certain customer record or sharing them among other staffers. Voice messages can be converted to text, a feature that saves time over manually entering notes and also allows voicemails to be searched, Ribbit said.

Customers can use their regular cell phone numbers with the service, as Ribbit's platform takes advantage of the "conditional call forwarding" features offered at no charge by some cell carriers. Calls made from a cell phone can be forwarded to Ribbit's Web-based platform, which in turn flows the data into Salesforce, the company said.

Users can also make software-based phone calls from within Salesforce. Their original cell phone numbers are still used as an identifier, but calls are routed over Ribbit's network, not the carrier's.

The notion of tying CRM to telephony is not new. For example, Cisco sells products for linking its unified communication offering to Salesforce and Microsoft's Dynamics CRM.

Such products are "interdependent on having a certain type of infrastructure," said Greg Goldfarb, general manager of software as a service at Ribbit.

"We're targeting a different, and we think, important area," he said. Namely "any Salesforce Professional Edition or above customer who's got a team of people relying on their cell phone to do their job."

Some 70 companies have been involved in the private beta period. Ribbit claimed a significant number are becoming paying customers, but declined to say how many.

Pricing for the service starts at US$25 per user per month, which includes unlimited voice messaging, storage and inbound calls to the software-based phone, along with five voice-to-text transcriptions. Voice-to-text service is an additional $10 per user each month for 40 messages. Unlimited outbound calling in the U.S. through the service's online phone costs $15 per user per month.

Ribbit is hoping the Salesforce application is just the beginning. To drive growth, it has used an increasingly common tactic, opening up a set of APIs (application programming interfaces) for Ribbit and creating a developer community around the platform.

This move came down to pragmatism, said Ribbit CEO Ted Griggs. "It became daunting as a startup to think, how are we going to do all these integrations?"

The company claims that more than 4,000 developers have signed up. It will make money through revenue-sharing deals with developers who create viable commercial applications.

Some initial efforts have created eyebrow-raising results. One developer created a Flash-based software version of the iPhone. Another made a softphone that looks like a chalkboard.

Ribbit is also set to launch a consumer-oriented phone and voicemail management service called Amphibian .