Back in November of last year, the location-based social event service Hot Potato launched at our Realtime CrunchUp. Today, they’ve taken what was a solid service , and made it a lot better with a number of upgrades. First and foremost, there is a new iPhone application that just went live in the App Store.

It’s getting tough to keep up with all of the location-related developments leading up to this year’s SXSW, and they just keep coming. Tonight, on the eve of the event, Plancast has just had its iPhone application approved. The service, which we’ve previously described as a ‘Foursquare for the future’, allows you to tell your friends where you’re planning to be as opposed to where you currently are (in other words, it lets you and your friends plan ahead).

Aol launched Lifestream , a social aggregator and publisher, as part of their AIM platform at TechCrunch50 Last Fall. Since then it has gained nearly 2 million users, say Aol.

Pelago knows that just about every location-based app in the world is seeking coverage right now just prior to SXSW where they will all battle Highlander -style.

Google launched a new service today in from its Labs called Google Reader Play . It is a more visual way to browse through the most popular items being saved and shared on Google Reader. When you launch it, you are presented with a large photo, video, or text excerpt on the main part of the screen, and can flip through by clicking on arrows or selecting an item from the filmstrip at the bottom of the screen

When Blippy launched a few months ago , the idea was to get the site up there as bare-bones as possible so it was simple to people.