A snapshot of Curees' progress from our Kitchen Cure Flickr Pool: Kitchen Cure participant windowshoppinginpjs shows us her freshly clean tile grout. She says: "After my husband pooh pooh'd our grout cleaning efforts, I showed him the before picture and he agreed it was indeed cleaner." Yay! We love deep cleaning week!
Previous Kitchen Cure Snapshot: An Organized Pantry
(Image: windowshoppinginpjs from the Kitchen Cure Flickr Pool)
A Work Week Menu Plan That You Can Do
How to Make Fresh Pasta Dough in the Food Processor
Good Food to Share 
The Big Book of Small, Cool Spaces 
Apartment Therapy Presents 
The Eight-Step Home Cure 
Floral Drink Dispen...
Small Cool Lessons: Discovering Small Space Design Ideas That Really Work
Beatriz's Fun & Functional Workspace
How did you clean your grout?
The link out to her flickr photo brings you to a description of what she used - Sun Oxygen Cleaner - but it looks like she doesn't really recommend it.
I used Sun Oxygen Cleaner ( http://www.walmart.com/ip/Oxygen-Cleaner-All-Purpose-Stain-Remover-Powder/13908578 ) which I purchased from Sam's Club. I believe it is the same as OxyClean.
I followed the directions on the bucket, and it basically said to use water to make a paste and apply it to the grout using rubber gloves and leave it there for an hour. Well, it dried up within minutes and was seriously hard as a rock. We used a lot of water to remove it and it didn't look any cleaner until we used a scrub brush and then it worked like a charm.
I probably would use it again, but I would put the paste down and scrub it immediately and wipe it up immediately.
I've used vinegar and a toothbrush with good results.
I used grout dye in my kitchen to lighten up some very dark grout, and it worked very well.
http://www.waldorfmodern.com/2010/01/kitchen-before-after.html
I also posted specifically about the dye and other tools I used for the kitchen makeover...
http://www.waldorfmodern.com/2010/01/kitchen-makeover-tools.html