They offer free software to induce you to use their PCB manufacturing services.  I've never used them, but quotes I've gotten from them seem competitive.

I've used the dry transfer stuff from Radio and had to deal with it flaking off.  I've used the press and peel stuff that you print out with a laser printer on special transfer sheet, then iron on.  That stuff works pretty well, but you need to follow the instructions very carefully.  I've had trouble with getting it too hot and also peeling it off too soon.

With both types, you can fix small errors in transfer using a "resist ink pen" (basically a standard indelible ink marker with a fine tip will do).  For gross errors, you're better off cleaning up the copper and starting over.

As for blank PCB material, the stuff that's readily avaible at Radio Shack or hobby electronics retailer should all be OK.  Your only real decision would be single or double sided (I'd start with single sided boards if you've never done it before.

another freebe which I have been using is available at http://www.pcb123.com. Again this is to encourage you to use their board manufacturing facilities. I find it most useful for drawing up schematics but have used it to produce boards. They all seem fiddly to use as quite often you have to design your own symbols and footpints. The idea is that you first draw the schematic and then convert that to a board layout via a 'rats nest' This is literally what it suggests - a mess of tracks and components which needs to be sorted out into a working layout. This bit I find very tedious and usually finish up doing most of it manually. I then print out a transparency of the pcb on OHP film with an inkjet and use that to expose photo-sensitive copper clad board in a homemade UV exposure box. The board is then developed with a suitable developer and etched in the normal way. It is possible to produce very professional results this way and is great if you want more than one board the same.

I used to use the rub down transfers to make similar transparencies but as Ratometer suggests they sometimes don't stick very well, especially if a bit old. If you want to use them straight on the copper clad board then the copper must be spotlessly clean.

When etching the boards I hang them vertically in a suitable container of etchant which stands in hot water to raise the temperature. I also aerate the etchant with an aquarium air pump and air stone to keep the etchant on the move. The container needs to be covered though otherwise you end up with a fine spray of etchant everywhere! Both heating and agitating the etchant speeds up the etching process greatly.

Hope this helps,

Print it to the shiny side of the backing paper on Avery laser printer labels with a good laser printer. Contact print it to really clean copper using a heated laminator. One with adjustable temperature & speed. I've made hundreds (almost) of boards this way.