Argon,
It is possible to use a 300D, though it's not the first choice. What everyone is talking about is a filter that's made into the camera to cut the light spectrum before reaching IR. However, it's probably not 100% effective, so some should still pass through. Then adding the IR filter cuts the light spectrum below the point of infrared, so effectively, most light is being kept from striking the sensor. This being the reason you need to increase your exposure time to make up the difference. This should help in understanding the need for a tripod. The cable release is just simply to help keep movement down, to avoid a blurred image if it seems to be a problem. But, you can always use your self timer, and a cable release isn't really necessary. Since the 300D doesn't have mirror lock up, the self timer is about as good as you can do anyway.. unless you want to install the "hack" firmware which adds the mirror lock up feature back. Just one of the things Canon thought they'd disable on the 300D. Note to, that even though there might be added noise due to the longer exposure times, this can be minimized with noise reduction. Here's a free one you can download:
http://www.neatimage.com
Next,
"Hot Spots" can sometimes be a problem because of reflections inside the lens it's self. If you find the center of the shot has a much lighter spot, you'll know you might need a different lens. This is due to some lenses less better coatings, and/or the type of optical formula the elements are made from. There's not an easy "get-around" for this. So just be aware if you notice it, where the problem comes from.
Another thing you'll find..
You'll need to focus (without the filter), and afterwards switch the lens to manual focus so it doesn't change when you press the shutter. After focusing, you'll then screw on the IR filter. This is required because the IR filter throws the focus point off. Plus, since the filter is dark to begin with, it makes it easier to see without the filter in place. Once you focus, you'll need to bring the focus back in a just a little (if I recall right), to make up the difference in focus point with the filter in place. Sorry I can't give you a specific amount, but it's going to vary by scene and equipment used. Just back the focus up a foot, or two. And hopefully someone will correct me if I remember wrong.
While I've seen some nice looking results using Freds' actions, it isn't quiet the same look to me. And if you've already purchased your filter, don't give up before you start. Once you do it a few times, you'll get the hang of it, and it won't seem a big deal.
Then as I'd mentioned before, the short processing description Allon gives should help you produce the results you're after.
Hope that helps clear some of it up,
happy shooting.