One of the most common techniques in DIY PCB etching is the toner transfer method. Tom added a twist to the standard method by adding the use of a stovetop in the toner transfer process. He wrote a tutorial describing in depth how you could recreate his results.
I have been trying out a new technique for toner transfer. Heat a cast iron hotplate on the stovetop to 175oC, as measured on a thermocouple, then turn the heat right down. Put a sheet of paper on the hotplate followed by the copper clad board, image side down. Then apply pressure with a rolling pin for 2-5 minutes. It might work for double sided, too.