Canon Eos T3 or Nikon D3100?

Please compare the two and why i should get one over the other! And also leave some suggestions. I'm looking for cameras or camcorders, slrs, dslrs around $400 and under that have HD 720p or 1080p.

Cindy are you sure that a DSLR is the camera type for you? I sold cameras for 10 yrs during my career and found that people need to match the camera to their skills or there intention to learn more about photography. Their is no doubt that a DSLR will give you the best quality, but we're talking 11x14's, 16x20's prints and larger. 4x6's & 5x7's even 8x10's are the same as a decent "bridge" type camera.
If you have your heart set on a DSLR let me recommend you get the camera with a 28mm to 50mm or 55mm lens. DO NOT consider a body and the 28-to-135mm lens, as this outfit is just too heavy to carry around. Especially for girls. I recently took a class on Photoshop Elements and the instructor invited students to bring in their cameras. A girl brings in her Canon outfitted with a 28-135mm lens. What a monster of an outfit! I also think your budget seems a bit low. Consider also that when you choose another subject like portraits, or macro (close-ups of flowers, etc) you are talking about buying another lens to fulfill the job, with a DSLR type camera. Incidently your budget is for a used camera as new can't be had for $400.00 You can buy the top of the line "bridge" cameras for around your budget.

Cindy, it's really the best advice to pop into your local camera dealer and have a chat with an assistant about what you are intending to do with a camera, and what you expect the camera to deliver. The assistant will be able to guide you through the most suitable cameras from the different brands within your budget, this will allow you to 'hold' the equipment and see which cameras and lenses you prefer, you will prefer one brand to another, not because of the name on the camera, but because it feels more comfortable in your hands.

I tend to recommend lenses in the 15-135mm range as a good starter lens, these lenses are more versatile than the 18-55mm bundled lens, again this comes down to personal preference and there's no right or wrong answer to this, it is more important that you are comfortable with the size and weight of the equipment and you will only be able to judge this by visiting your local camera shop.

Whatever you decide to buy… Enjoy!

I recommend Nikon D3100 due to its good features, better market and high image quality.

I would like to show what professionals say about Nikon D3100, hope it will help your decision:

http://www.amazon.com/...2Q4KNDSWK/

If we compare both the cameras, we will find that features of D3100 are better than T3 and obviously the performance and the image quality will be better too. Here is a brief comparison for you:
D3100 Shoots higher resolution Full HD (1080p) video but at a lower frame rate.
The D3100 has a slight edge (0.3 f-stops) in low noise, high ISO performance
Distinguishes 0.6 more bits of color
Around 10% better image quality than T3
Around 10% larger sensor
It has a self cleaning sensor which removes dust from the sensor automatically, avoiding spots in photos.
T3 is 12.2 MP while D3100 is 14.2 MP so it capture around 20% more detail in your photos
Around 10% less delay when taking photos
Set focus accurately within the frame and it more portable than T3

It also matches your requirement of 1080p video shooting