Just when you though this week was done with smartphone leaks, two more are coming our way. The folks over at Engadget have come across leaked slides for three new smartphones from Dell. Two of them are affectionately named Thunder and Lightning.

The two smartphones are quite fetching and take advantage of two of the most high profile operating systems out there -- one of which has already been released, and one of which is still at least six months away.

First up is the Dell Thunder. This candy bar-style phone is dominated by a 4.1" (WVGA) OLED display, features an 8MP digital camera, and includes HSDPA support (AT&T). According to Engadget, the Thunder will also receive -- drumroll please -- a integrated Hulu app for viewing movies and TV shows. We've heard rumors about a mobile Hulu app for ages, but this could be the first time that we actually see it show up in a shipping product. In addition, an LTE version of the Thunder is expected in 2011.

Next up is the Dell Lightning. This slider phone runs the upcoming Windows Phone 7 operating system and features HSDPA 7.2Mbps 3G connectivity (AT&T and T-Mobile). The screen is a generous 4.1" (WVGA) OLED unit, and an autofocusing 5MP camera is on the back of the device. The Lightning uses a 1GHz (QSD8250) Snapdragon processor, includes 1GB of flash and features 512MB of RAM. All required Windows Phone 7 hardware features are also included (i.e. GPS, accelerometer, etc.).

Not to be left out, there's another Dell smartphone coming your way running Android Froyo. The third phone, named Flash, features an 800MHz Qualcomm processor, 512MB RAM / 512MB ROM, 3.5" WVGA display (sorry, no OLED with this one), Bluetooth 3.0, and TV-out. The Flash will be available for AT&T's network early next year.

Interestingly, Dell says that this phone features an "innovative design with unique curved glass". I guess we need to see this phone in the flesh to see what Dell is talking about, but that won't be for a while.

It's good to know that there are plenty of iPhone alternatives out there now, and more coming in the future. We've already seen a strong showing with the Droid Incredible and these new offerings from Dell should do quite a bit to make those that are sick of hearing about the iPhone stand up and take notice.