Czechsite.com
A guide to where in Prague you can wash your laundry in public.
http://www.czechsite.com/laundry.html

Job Monkey.com
Index of laundromats in the city.
http://www.jobmonkey.com/teaching/europe/html/laundromats.html

Laundryland Praha
The chain has outlets in various locations around the city.
http://www.laundryland.cz/

Prague "Cyber" Laundromat
A laundromat that doubles up as a cybercafe.
http://www.volny.cz/laundromat/