iSkoot, the company that first got attention by allowing you to make calls on your mobile phone through Skype’s Internet call service, is launching a new software development kit (SDK) that it says will let standard mobile phones add the kinds of web services and applications that make devices like Apple’s iPhone so popular.

Basically, this means manufacturers can now bring Facebook, email, instant messaging, RSS feeds, and Twitter (all under the umbrella of iSkoot’s KalaidaLive platform) to an old-fashioned mobile handset — say, the cludgy Nokia that I shocked people with at tech parties before I replaced it with an iPhone 3G. We wrote about iSkoot’s mobile platform back in November, when we’d heard it was building the platform for AT&T. Now that platform is  available to any handset manufacturer.

An iSkoot spokeswoman says one of the big benefits to KalaidaLive is the fact that its applications use “push” technology, allowing them to update in real-time. However, most of the work is being done on the San Francisco company’s servers, so that it’s not putting a big strain on the handset.

And just to be clear, this SDK is much more limited than, say, the iPhone SDK — it’s not about allowing third-party developers to build applicaitions, just making it easy for manufacturers to add iSkoot’s applications to their devices. This continues the company’s move away from being a voice company, and more of a competitor to mobile social networks, espepecially mig33, which also tries to enable a number of social experiences on relatively cheap phones — except, of course, that iSkoot is also trying to create ways to plug into existing networks like Facebook, rather than build its own.