Dell has been sidling quietly into the mobile phone business over the last year or so, but things are about to get serious. It's been revealed that the company is working on a portrait QWERTY slider that runs Windows Phone 7 called the Dell Lightning.

It's part of a host of other leaks, which we'll detail in full elsewhere, but it's most certainly the flagship, packing a 1GHz processor, 4.1-inch OLED display, 5-megapixel camera, 1GB of internal memory plus 512MB of RAM, an 8GB microSD card, GPS, accelerometer, compass, FM radio and full support for Flash. Impressively, it looks like it's also due to be getting a 4G LTE update in late 2011.

It's due to arrive in Q4 2010, meaning that it'll be among the first to arrive with Microsoft's next mobile operating system pre-loaded. We don't have any ideas on pricing just yet, but no doubt we'll hear more details on that as the device approaches release. We'll keep you posted.