If you already have a memory card, take it to the store and get the sales assistant to put it in the display camera.. Take a few shots that you think will test it...take the card home and look at your images...if you are happy with the feel of the camera and the results then go back and buy it. If you do not have a card, buy this first and tell the salesperson you will be back.....john
I am on my second DSLR (my wife uses the first) since 2005. A number of points 1. Once you choose your brand stay with it as the lens's will fit the next model. Therefore choose carefully and take extra time to make the initial brand selection 2. Before you do what the vast majority do and choose between Nikon and Canon, take a look at the Olympus, Pentax and Sony. All these have image stabilisation in the body and you do not need IS lens's. Talk to friends, get opinions, talk to camera shops and most importantly hold the cameras. 3. Once you have narrowed your brand choice then you have another choice to make a) kit lens deals (2 lens plus body) and wait until you understand more to upgrade to higher quality lens One expensive lens to start with.
I am not going to push my brand of body down your throat because everyone has different opinions. On the lens side, I would go with the kit lens deals and then take my time to evaluate if and when I upgrade but others will suggest you go for one good lens to start with. Remember that the body will be superceded within 12 months but the good lens will last many bodies so, before you buy an expensive lens, be sure it is what you want.
I have had (my wife now uses it as I have a Sony A700) a Konica-Minolta 5D and the software will run on a Mac or a PC. I have used the KM software but now use Picasa2 to download the images and Photoshop and Photoshop Camera raw for manipulation....john