Go to Kragen, AutoZone, Pepboys, any of those places and also try Wal Mart (what don't those bastards sell! ) But I have found them in auto parts stores.
I got them from menards, they were in a section of bathroom stuff that was all suction cup stuff for the shower and such. They had little plastic hooks on them, I think they were $1 a piece. I'd imagine you could find them at other hardware stores or bath/bedroom supply stores.
As far as a diy pictoral, that I don't have. But you basically just get 4 1/2" 90's and grab some 1/2" pvc and cut it to size as well as the eggcrate and zip tie it together. I drilled holes in the pvc it's self to try and let water circulate so it doesn't become stagnant. For the suction cup holes I started out with a small drill but to start the hole and then got one that was slightly smaller than what I thought was needed and worked my way up till the suction cup fit.
If you want to get fancy you could cut slots in the pvc and put the eggcrate into the slots, it'd look a lot cleaner, but I really just didn't feel like putting that much time into it.
) But I have found them in auto parts stores.