Loopt demonstrated its LBS app for the new 3G iPhone at the Apple Worldwide Developers Conference (WWDC) last month, but it is adding some more features –for free.

Besides the friend-finder application, iPhone users will be able to use Loopt to get reviews of places such as restaurants, thanks to a deal with content partner Yelp, and see where their friends have been. Another new feature is the ability to use Loopt to instantly update all your online communities and blogs with location, photos and comments.

Loopt plans to monetize the free iPhone apps by introducing its first location-targeted advertising, but that won’t start immediately and it will be unobtrusive so people aren’t getting spammed with ads, said Loopt CEO and co-founder Sam Altman.

Altman, who was a sophomore computer science major at Stanford University in 2005 when the idea emerged for the Loopt service, said he was thrilled to be part of the demonstration of apps during the WWDC, admitting that he’s a huge Apple fanboy “for life.” He co-founded Loopt with friend Nick Sivo because they wanted to see where their friends were at any given time.

Loopt is entirely permission-based and the company regularly works with organizations such as the Family Online Safety Institute, ConnectSafely.org, the Center for Democracy & Technology, Progress & Freedom Foundation’s Center for Digital Media Freedom and the Internet Safety Task Force.

Loopt has been on a roll lately. In late June, it announced the Loopt friend-finder and mapping service is available on select Verizon Wireless phones for $3.99 a month. Earlier, it announced the LBS service is available for free to BlackBerry users on the Sprint, Alltel, T-Mobile USA and AT&T networks, although it has since been taken off the Alltel devices for reasons that aren’t entirely clear.