San Diego has another startup — this one focused on expanding the content of instant messaging services by essentially turning your cell phone into something like a Walkie-Talkie — only much, much cooler and far more complicated.

Rocketalk is a free messaging software application that can be downloaded online by anyone with a compatible cellular phone. The list, for now, includes only Nokia phones Symbian Series 60 and Windows 2003. The company expects to expand that list to 150 phones in six months.

The technology can send video and photos as well as voice and text messages. All messages can be sent to a PC if the recipient doesn’t have Rocketalk on their cellular phone.

Rocketalk has had a developed product for six months and is now just beginning to build its brand, says Julia Wilson, v.p. of business development. Rajiv Kumar is CEO and founder of Rocketalk. Kumar previously founded Wivecom, a Bluetooth company that was sold to Broadcom.