I signed up for The Writer's Workshop over at the blog Mama's Losin' It. She has you write to a prompt, post it on your own blog and then link back to her site. Click on either link (one goes right to the workshop page, the other to Mama Kat's home page) to get the info and directions.
I highly suggest signing up for the email reminders because I personally find that the prompts for the week, that you can link back to her site with, are NOT easy to locate. She has general writing prompts up, but they are not the same ones I got in the official weekly email. Just a thought! ;)
Please note that down on the right, there is a link for this workshop also, under Mama Kat's Writer's Workshop.