[eluser]TheFuzzy0ne[/eluser]
Just to be sure, you will need to escape that hyphen, so:
Code:
$route['([A-Za-z]+\.[A-Za-z\-]+)'] = 'main/index/$1';
I'm sure you got it right though, as I'm sure that would have resulted in a parse error otherwise.
Oh, and one last thing - Welcome to the CodeIgniter forums!