I have some files PHP files that do not have any extension. I would like to know how I can make PHPED to recognize these files as PHP files and hence highlight the code just as an ordinary file with .php extension.

Tools > Settings > IDE > Associations

Add * to your list of PHP4 or PHP5 file associations (dependent of if you want the file to be associated with PHP4 or 5). So, for example, your PHP4 line would look something like this:

*.php4;*.inc4;*

The ";*" on the end is what you will add

Thank you very much, nothsa. This is working