How can you recover your singing voice?

Haha well, I'm trying to do the exact same thing. I was in choir for a couple of years and I sang (hopefully) pretty nicely, but I've fallen out of practice. Here's what I've been doing: Practice singing songs you like to the radio, then sing them in a higher key than they actually are, or, if it's a man singing and you're a woman, an octave higher. If you have a piano, you can sing as you play with it or, if you can't play it, pick a note to start on and play it once, then sing from that note, and once you're done play it again to see if you've gone sharp or flat.

Just practice, pretty much, and you'll get it back :) It's working for me.

(If you're talking about having lost it recently and need to fix it in time for a concert or something, then drink tea with honey and/or eat soft and warm foods for your throat [like oatmeal].)