I currently have a cannon digital rebel xt with an 18-55 lens, I fing that there are alot of situations where I want more zoom. what size would you reccomend?
I also would like something that will allow me to shoot in lower light without flash, maybee an image stabilized lens?
Does the lens itself have nything to do with the depth of feild? Meaning is there any spec like a numerically smaller aperture setting I should be looking for? this sounds expensive already LOL
Thanks for bearing woth me I am kind of new to this!!

Sounds like you should do a lot more learning before you spend much money on another lens. Or just buy the cheapest zoom lens one step up from your max focal length of 55mm like this:

Canon telephoto zoom

For low light, there is no substitute for a tripod. If you are trying to get around that by purchasing a wide aperture telephoto zoom with image stabilization, you are looking a a large expensive lens that would be tiring to hold without a tripod (or monopod) anyway.

You might consider a fixed focal length lens instead of a zoom. You did not say why you want a longer focal length. You could get a lighter, smaller lens with a wider aperture by using a fixed focal length lens. Canon has a vast array of lenses. With the popularity of zooms, they have gotten away from fixed focal length lenses unless they have very larger apertures, L glass, and a lofty price. But they will have a wider maximum aperture if that is your primary goal.

The lens I have now is an ef-s series 18-55 and I want a more powerfull zoom for taking pictures of my kids scenery ect, without having to get closer, not really looking for a huge zoom just something with a wider range for more flexebility for genral use, I may buy another one like the one you mentioned for sporting events and racing ect where I would want a little more yet and that 75-300 would be multiplied by 1.6 if you were to put it on my ef-s series camera from what I understand.
is image stabilazation worth the extra money for a genral purpose lens?
I am primarily after something more flexibleas far as zoom, if a tripod is the way to go for light so be it

If you are hand holding the camera, image stabilization is worth the money, especially with the longer focal lengths which will amplify camera shake.

Only the pro level digital slr's have a sensor as large as 35mm film, so the effective focal length on many slr's has a multiple, commonly 1.6. That is a big plus on the telephoto end but a big minus for wide angle lenses.

So the top 300 mm focal length of a zoom for your camera would be like using a 450 mm lens on a 35mm camera. That is good for sports, action, wildlife - especially with image stabilization and a monopod.

A carbon fiber monopod like a Feisol weighs almost nothing and makes the camera much more stable. With a long telephoto, it is nice if the lens has a tripod socket which provides better balance than using the camera's socket. Using the monopod, spares your arms or your neck from extended periods of waiting for the shot with camera in hand/neck.

This would be the best, non-L series Canon lens for your purposes but is much more costly than your current lens because of the ED glass and IS:

70-300

I think a used ef lens in the range you mentioned will work and I will just get a monopod for using the zoom, most of the time I will be using it will be at motorsports events where I will be using a fast shutterspeed anyway so I think I can get away without it, I would like it on a smaller lens though because it will be used by hand.

If you are using it for motorsports then you would love the monopod. You can pre-focus on a turn and use your body with the monopod for a de facto tripod. Or you can use the monopod for smooth panning with long shutter speeds for a nicely blurred background. Also, if the event is crowded, having the camera on a monopod lets you establish more physical space without people crowding you out.

I looked up used monpods on Ebay and they are not much of a bargain and most of the used ones are heavier aluminum. For the money, I would buy a new Feisol carbon fiber monopod. For your gear, you could get the smaller one (CM-1401) which I have used with a Pentax 67II with 165mm lens:

Feisol Monopods