Airwalk Communications is part of a wave of companies developing “femtocell” technology, which lets your cell phone run on your home WiFi networks and allows you to route calls over your land-line too.

The Richardson, Texas, company has just finished raising $25 million in a second round of financing.

Deploying femtocell access points is expected to be a major trend this year and next. Airwalk faces competition from a range of players, including Ubiquisys, based in Swindon, UK, and backed by Google, among others.

Others competitors include RadioFrame Network and Airvana, not to mention large companies Alcatel-Lucent, Sony Ericsson and Samsung. Airwalk hopes to go to market in early 2009.

Airwalk has now raised $41 million in total. The latest round was led by Sevin Rosen Funds. Other investors include Alta Berkeley Venture Partners, Duchossois Technology Partners and TL Ventures.

Ubiquisys has now raised $37 million.

Femtocell technology is just one of the alternatives to fixed-mobile convergence, a trend toward a world where you can call over both your fixed or cell line, whatever is cheaper.

Most competing technologies, however, require a new (dual-mode) handset, whereas Femtocell doesn’t. It can be used with existing devices (cell phone) and operate on local home networks and can be hooked up with the home’s land-lines or through VoIP.

Carriers would sell the technology to consumers, pitching it as a way they can lower mobile subscription costs. Sprint already is testing femtocell in some areas.

The femtocell technology also promises to improve transmission of IPTV and high-bandwidth services.