Kiwi's probably right. You're going to lose light (even the best teleconverters cause you to give up light), and most P&S cameras already do all they can to gather enough light for their sensor. This means that you'll lose optical resolution (not megapixels, but clarity) because there won't be as many photons hitting the sensor and creating the image.
This is the reason that most DSLR manufacturers recommend at least f/2.8 lenses for teleconverters. An f/2.8 lens has the big glass elements to gather a lot of light, so it can afford to sacrifice some to a teleconverter (also they can provide enough light to the AF sensors to keep autofocus working). Even with gear like this, you give up some clarity. To give you an idea, I recently tried out an Nikon f/2.8 300mm prime lens along with a TC-17II 1.7x teleconverter. This was top of the line gear ($5000 lens, $250 teleconverter). The lens gave up 1 1/2 stops to the teleconverter, which made the max aperture f/4.8 with the teleconverter attached. Even so, I had to stop the lens down to f/6.3 in order to maintain the clarity that the lens had without the teleconverter (even then, it wasn't quite as sharp as the lens by itself at f/2.8).
Of course, I'm speaking in generalizations, and your particular camera might do well enough with it for your purposes. I'd at least make sure you get a good return policy from the vendor if you decide to try it. That way, you're not out $90 if you find it to be disappointing.
