Navizon Peer-to-Peer GPS - GPS Review: "Navizon has been working in beta (testing) mode since August but has recently officially launched their service. Their service basically provides location based services without a GPS receiver. The application works by utilizing location information from wifi networks and cellular networks to approximate your position.

“Instead of satellite signals typically used by GPS devices, Navizon uses signals from nearby Wi-Fi and cellular towers,” said Cyril Houri, founder and CEO of Mexens Technology. “By looking at the surrounding wireless landscape, the device knows where users are located and can thereby offer location-based services.”

“Let’s say you’re in a restaurant and want to post a comment about it—you can create a Geo Tag and when another Navizon user enters the vicinity, the tag you posted will pop up on his device,” Houri said.

“You can use this feature in other ways too—you can program a Geo Tag next to your corner deli to remind you to buy milk and each time you pass "