I got two of these little mailboxes from Target's dollar section. Unfortunately the doors aren't hinged like the one in the picture, but they pop on and off easily enough.
I cut up a piece of poster paper into sizes that would fit into the mailboxes (I suspect index cards would be easier, but I didn't have them). I wrote simple words on each card: cat, sat, mom, dad, on, in, hat, pot, pop, you get the idea.
I put one into the mailbox and put up the flag. Choclo siezed it, shook it around and sang, "We just got a letter..." (Thank you Blues Clues!). Then he opened it, spun the card around a few times, and sounded out the word (c...a...t). He then asked me what it said, I sounded out the word exactly as he had done and he then announced, "It says, 'cat!'" We did this over and over and over. We started stringing the words into sentences like, "Choclo sat on Mom." Key: we stopped before he was tired of it. Stopping before they want to stop is a fantastic tool in teaching reading (or anything else).
Eventually he will get tired of spinning the card and sounding it out slowly and asking me to repeat him. Right now that's part of the game, but probably for only a few days. And then... Bob Books!