Programming :: Command For Find/Replace In Text Files (inc. Files In Sub-folders)?

I found this command that works great finding and replacing a simple string to another in files located in that folder and all sub-folders.

Code: find . -name '*.php' | xargs perl -pi -e 's/OldText/NewText/g'

The problem I have is that I need to replace a more complex string, like this: Old string: /mnt/stor6-wc2-dfw1/627896/982574/ New string: /mnt/stor8-wc2-dfw1/369587/302589/ There I don't know how to do it... since the / is what separates the old from the new strings, and the strings that I want to replace have / in it. Also, I would like to know how to specify under what folder replace the files, for example, I want that it search/replaces all files under /var/www/mysite/htdocs folder.