Yes whoever owns the address you wrongly sent the BTC to can access it. It is now THEIR BTC to do whatever they want with it.
As for getting it back - it all depends on:
a. if you know who owns the address you (wrongly) sent it to
b. can contact them and then
c. convince them to return the BTC.
Good luck with all that...
But does all wrong addresses actually exist... Like does it always go to another account when you make errors???
[/quote]Only IF the address you entered is a valid receiving address created by someone.
AFAIK it is possible to send to a entirely random address that no one owns in which case the coins are gone forever aka, 'burned'. All the chain logic does is verify that the address format is correct - does not and cannot check if it is a 'real' address owned by someone.