I've made GeolocMock. If your PC has no geolocation devices, IE9 uses a webservice to determine your location. GeolocMock uses FiddlerCore to intercept the response from the webservice and allows the user to replace the location in the response with another. This was a fun weekend project in order to play with FiddlerCore, the W3C Geoloc APIs in IE9, hosting the IE9 WebOC in a .NET app, and the Bing Maps APIs.
Internet Explorer 8 Beta 1 is available now. I can finally talk about some of the stuff I've been working on for the past year or so: activities. Activities let you select a document, some text on a document, or a link to a document and run that selection through a web service. For example, you could select a word on a webpage and look it up in Wikipedia, select an address and map it on Yahoo Maps, select a webpage and translate it into English with Windows Live Translator, or select a link and add it to Digg.
IE8 comes installed with some activities based on Microsoft web services but there's a page you can go to to install other activities. However, that page is missing some of my favorites that I use all the time, like del.icio.us. Accordingly, I've put together a page of the activities I use. MSDN has all the info on creating Activities.
Activities are very similar to other existing features in other browsers including the ability to add context menu items to IE. There's two important differences which make activities better. Activities have a preview window that pops out when you hover over an activity, which is useful to get in place information easily provided by developers. The other is that the interface is explicit and takes after HTML FORMs and OpenSearch descriptions. Because the interface is explicitly described in XML (unlike the context menu additions described above which run arbitrary script) we have the ability to use activities in places other than on a webpage in the future. And because activity definitions are similar to HTML FORMs, if your webservice has an HTML FORM describing it you can easily create an activity.