The E-TEN M600+, an upgrade of the original M600, brings with it some useful improvements: "more memory, higher resolution camera and improved Bluetooth."
The specs on the M600+ are a 400Mhz Samsung processor, 256MB of memory, 2.0-megapixel camera, the Windows Mobile 5 push email software update, WiFi, GSM, GPRS, Bluetooth 2.0, 2.8" display, and SDIO expansion. Since the original was Skype compatible, this should be also. The improved specs should make call quality even better.
The only availability is "Soon", and expect the price to be higher than the M600, obviously.
E-TEN M600+ Pocket PC phone officially launched [MS Mobiles]