Kind of, but don't confuse the hash that a miner needs to find, with a bitcoin address.
A bitcoin address is the thing that looks like a string of uppercase/lowercase letters and numbers (frinstance, the one in my sig). It always starts with a 1, has (I think) 33 or 34 characters, and each character is one of 58 (not 62). 26 uppercase letters + 26 lowercase + 10 digits = 62, but four are disallowed (I think 0, O, 1 and l) and you can probably see why.
The hash is a 256-bit number, which must start with a certain number of zeroes. The more zeroes it must start with, the harder it'll be to find. Back when the difficulty level was 1, the first 32 bits had to be zero. That meant that on average you'd have to make 4 billion hashes (actually 2^32) to find a valid block header. Now the difficulty is six-million-and-change, which means the upper limit for what's a valid hash, is six million times lower than it was back in the day. So your miner has to do six million times as much work as back then.
For more info on what's actually being hashed, check out
https://en.bitcoin.it/wiki/Block_hashing_algorithm