Google announced 2 new ways to make your apps location aware yesterday. One's a web service that any web can take advantage the second is built into Google Gears, and runs on the mobile version of this plugin.

Ajax API property:

First, there's the AJAX API property that provides a simple way to get an approximate, region-level estimate of a user's location based on their IP address. It's as simple as referencing google.loader.ClientLocation, which is made available using the Google AJAX API Loader. This API does not require users to install any client-side software.

Google Gears Geolocation API (Windows Mobile Only for Now as TechCrunch notes)

the Gears Geolocation API provides a way to get a more precise estimate of a user's location. On mobile devices with Gears installed, the Geolocation API can use the cell-ID of nearby cell towers or on-board GPS (if either is available) to improve the postion fix. In the near future, we'll be adding data from your WiFi connection to improve accuracy even further, on both desktop and mobile. In all cases, Gears takes care of assimilating the results from each source and returning the best available position estimate.

Google Gears Mobile still only runs on IE Mobile, but this should in IE and FireFox on the desktop. There's other ways to get Geolocation on mobile apps, but this is nice because it comes from the browser so web apps can easily take advantage of it.

Of course privacy is a concern, but they seem to have dealt with that in an acceptable way:

The first time your site calls the Geolocation API to request a user's location, that user will be shown a permissions dialog where they can choose to allow or deny your site access. Users can change that decision at any time via the "Gears settings" dialog in the browser menu. Google does not keep location information about users when your site uses the Geolocation API.

Emphasis is mine.

Let me know if you've worked with or are interested in geolocating your app!

Read more from Andre Charland.