If you havecorrectly written your SD card then you should be able to see a small 74MB partition thatcontains the Pi boot files. What software are you using to write the card? Also what card reader/writer? I have found that i get far better results with an external device such as
http://www.amazon.co.uk/gp/product/B000 ... 01_s00_i00 (or an equivalent). Having such a device is useful as once you have your Pi working you can write SD cards directly on the Pi with such a device.
One problem with getting a pre-installed card is that it will almost certainy come with out-of-date software on it. With the rate at which the Pi system software is still advancing then this can matter. You will therefore definitely want a way to write your own SD cards at some point.