Har har. I actually wrote quite a lengthy post about it when I was at the lab, but the connection seemed to hit a snag and I couldn't post.
Basically, they're small self-contained computers with a greyscale LCD, a simple speaker and large keys with braille markings. Each polling table has one, connected to a small keypad where the chairman of the table types in the voter ID (well, it's a special document for voting, really, everyone must have one). Once the Id is typed in, the voting starts for that person - the machine will display the current vote (president, governor, senator, etc.) and the voter will type in the candidate number (all parties have a fixed number which doesn't change between elections, and all candidates have a number which starts with the party number - governor and president candidate numbers are simply the party numbers). Once the number is typed, the machine plays a distinct sound (of many), shows a photo of the candidate (only for president, governor and senator, I think - not completely sure, though), and asks for the voter to confirm or cancel the vote. If he confirms, it plays a sound and proceeds to the next vote on the list, if not, the voter can type another number. There's a special key to vote null, and a key to skip a vote (same as an unmarked ballot). Once all the votes are finished, another sound is played, the LCD shows "END" (in portuguese

), and it's over. The chairman then types the Id of the next person in line.
A few days before each election they put the machines with bogus candidates for the voters to practice, and this training is encouraged through ad campaigns on TV, radio, newspapers, etc. There are hardly any lines on the polling spots (I never stood more than five minutes in line), and the machines rarely break, even if dropped on the floor. Counting is done digitally - the machine prints the results (for conference by the party auditors) and records the results on a disk (encrypted, of course) which is read by a counting computer. Counting is over in the same day, even for presidential elections. Party auditors can monitor the whole process, from the voting tables, to the disk transference, to the actual counting, and they usually do, so there isn't much room for tampering. The machines themselves are sealed, and can be audited by party-appointed technicians. The staff for the polling tables is picked at random from the pool of voters (several friends of mine with no party connections and no interest in politics whatsoever were picked already, so it's pretty clear that it's actually random) - polling duty is mandatory, and if you're picked and refuse without a very good excuse you can go to jail.
Here's a picture of one of the voting machines:

And this is a simulator (in Java) from the official Supreme Electoral Court website:
http://www.tse.gov.br/eleicoes/urna_eletronica/simulacao_votacao/UrnaApplet2.htm