From the link that Fotoace put up you can see that it is possible, a 6 second exposure at f11 is not too long. Focusing would be a problem as IR focuses in front of the sensor, but a few test shots would sort this out and at f11 on a landscape picture wouldn't really be a problem anyway.

One way to test your cameras IR response is to use a small aperture (you need a long shutter time) and point your TV remote at it, if the picture shows a glow around the IR diode then your camera is probably sensitive enough at least to give it a try, you'll only be out the cost of the filter.

A good IR filter is a piece of totally exposed B&W film if you have any lying around. It would have to large enough to cover the lens so 120 film is favourite.

A lot of Astro photographers take out the IR filter (Canon is particularly easy) and replace it with clear glass, then their camera records the very wide spectrum needed for shots of Nebulae, which are often 10 minute exposures by the way. Not that 10 minutes is the limit of the camera (there's no reciprocity failure with digital sensors) it's a limit of their tracking systems.

Which reminds me, if you really feel like experimenting and pushing the limits of your camera, go into the middle of nowhere on an overcast moonless night, where you need a torch to see your way. Put your camera on a tripod, select low ISO and a small aperture, set your camera onto 'B' mode and lock the shutter open for 10 minutes or so (some experiment is require it may be 20 minutes), turn off the noise reduction feature or it will take forever to record the 'dark frame'. The camera will just sit there quietly recording photons, you'll be surprised at what you get, a full colour picture with a very eerie light. The totally black sky will have a glow and you will see all the detail - it really is amazing. Just make sure your battery is fully charged.

Chris