Most of my clients provide the copy for the job but occasionally they will ask me to recommend a copywriter. In this case I have a couple of contacts that I have worked with in the past, met on buisness forums etc... that I can recommend. Your best bet is to start networking.
You may find it easier to create your image in Photoshop and then drop this into Quark, Indesign or even Illustrator to add your copy (your copy will look crisper when it prints this way too).
As far as sizes are concerned, flyers can be almost any size you like. Say the flyer was A5 (148x105), as a rule of thumb, you would need to add 3mm all around. It needs to be at 300dpi at actual size. So if you were creating it in Photoshop for example, your total document needs to be 154x111mm and 300dpi.
Unless you have a white background, your image needs to go right to the edge in case the cutter moves (don't just leave a white gap) and bear in mind that 3mm will be trimmed off each edge.
Hope this helps, if you need any more help just shout...
