My neighbor showed me how to do this and I love it! All you need is some flowers or flower petals, watercolor paper or a piece of fabric (we used an old sheet torn into pieces) a piece of paper towel and a hammer. Place the flowers on the fabric, (remove stems as close to flower as possible) cover with a paper towel and hammer away. The colors come out looking like watercolors. This is my first project but I think if you work with the placement you could make it look more like a drawing. I' folded mine together and will sew the sides and fill with dried lavender or dried roses. You can fold the fabric in half and put the flowers inside if you want. She is supposed to send a video on how to and if she does will post it. Not sure what the process is called.
Got the video and it shows using a piece of clear plastic instead of a paper towel but either works. The process is called Hapo-zome. I don't know if you could use something to seal it or if it would last through a wash.
http://vimeo.com/28543186 and here is a link to a fiber artists work showing some examples. http://www.indiaflint.com/