Yes, they are pronounced with the same sound. There is a very easy pronunciation rule in Portuguese that says that the C letter before A, O, and U, always sounds like a K sound; before E or I, however, it sounds like an S sound. So, if we spelled 'conheco' without the cedilla symbol, it would sound like 'co-nhe-ko'. To make the C sound like an S sound before A, O, and U, we just add the cedilla to it and that's it (never before E or I, because, again, the C already sounds like an S before those ones). That's why 'conheço' (and the other conjugations you mentioned) has that symbol: to make it sound like 'co-nhe-so'. Why don't we spell it with an S, then? Because of another rule that says that an S between two vowels sounds like a Z sound, so 'conheso' would sound like 'co-nhe-zu'. We can also overcome that rule by doubling the S ('asa': 'a-za'; 'assa': 'a-sa'), but I think the choice between SS or Ç has to do with orthography, the word's roots, spelling patterns, etc. (If you've kept up with the explanation so far, you might be asking yourself: so, if the C before E and I always sounds like an S, how could we create a KE or KI sound combination? Well, that's what the useless Q letter is for in Portuguese. ;) Just attach a U between it and E or I, and there you are. The U may or may not be pronounced and to know that you need to look the word up in a dictionary and learn by heart: 'quente' sounds like 'ken-te' (no U), but 'frequente' sounds like 'fre-kwen-te' (U pronounced very quickly, with emphasis on the next vowel).)

Hi August, What is important to know is that the sound of the ç is the same of "s". Thus the verb "conhecer", the sound of the sylab CE is is equal to SE, than if you write CO, the sound is like (KO). This is the reason to spell ÇO. Resume, take care with the sound ÇA CE CI ÇO ÇU (sounds like SA SE SI SO SU).