Removing ^M characters

hi

I have a perl script conv.pl. when i execute this file and direct i to log file I see lots of ^M characters in the log file. There is no ^M in conv.pl file. Log file is generated only after conv.pl is executed.
Please help as how to get rid of these.
This conv.pl is going to get schduled in crontab so I will have to get it fix before hand only and not after log file is created.

$> conv.pl > a.log

Thanks