ok, back to the question:
there are a few ways to go with using stomp boxes to have fun with vocals.
the big first division is: do you want to put the mic straight into the stomp boxes are deal with the stop boxes later?
to go straight in, i would either use a reverse DI box, or one of those impedance matching do hickeys. go right into the stomp box world and have fun. it's gonna be lo fi. but probably a heck of a lot more interesting sounding than fucking with the vocals later using plug ins. also you can get a great vocal performance when the person singing is hearing all the delays and distortions etc.
the other thing to do it just record the vocals as you would normally, then either as an insert or as an aux "reamp" the signal out to the boxes. you get a bit more control with this method, but lose out on performance perhaps...
i like recording vocals clean on the computer, then using an aux out to fuck with them. distortion pedals and guitar compressor pedals sound 50 billion times better than the distortion plug -ins i have heard.
lately i have been digging puting vocals through a DOD 280 which is one of those DOD pedals from the "we want to be MXR" days. it is optical, has a nice slow attack and a very nice limited bandwith. great as a vocal effect.-