Skype API

Skype recently announced a partnership with Siemens to enable cordless phones to use Skype to dial out (in addition to using the PSTN):

Skype's free Internet telephony software works with Siemens phones via the Gigaset M34 USB adapter, an open interface adapter that is plugged into the USB connection point of a users' PC. It communicates with the phone’s base station to either make or receive a Skype call. The handset then enables users to gain cordless access to the extensive Skype features including, free Skype to Skype calling, buddy lists, the Skype Global Directory and conference calling.

Skype has also recently opened up an API enabling hardware devices and software applications to integrate with Skype's software. A couple of interesting applications called out:

Call-center and IVR solutions
Although Skype has so far been designed primarily with individual communication needs in mind, it can be used to provide business-class calling services through the Skype API. Businesses can provide Interactive Voice Response (IVR) solutions where the software answers the inbound Skype call and provides the user with automated choices and selections in combination with a back-end system. This could be used for ticket booking, payment, pizza ordering and many other services. The IVR system can be either fully automatic or a combination of operator/automatic usage.
For service monitoring purposes, the calls to operators can be recorded and later screened using regular audio manipulating tools on a standard PC. The information can be automatically stored and emailed.

Phone handsets
Skype provides access to its functions from software a well as hardware devices. The Skype client software can be used with any audio hardware compatible with the operating system, such as headphones and a desktop microphone, or a dedicated USB headset or even telephone-like handset. However, all of these require the user to still work with Skype software and sit behind a computer.
Users may want more freedom both in home and business environments and not to be tied to a computer. This is why Skype has joined forces with Siemens as its first Preferred Cordless Phone Provider to give users a chance to move about freely. The Siemens M34 Gigaset USB Adapter plugs into the computer’s USB port and connects to a Gigaset base station that in turn is connected to one or more cordless handsets. The handsets have access to basic Skype functions like placing and answering calls and navigating the contact list.
The Skype API gives other hardware manufacturers an opportunity to build similar solutions in their existing or upcoming products. Note that for using all these functions, a computer running Skype is still required.