I'll help with the regex requirements.

#/usr/bin/perl -w
use strict;
my $text = "<tag>\n\tThe purpose of the applicant rating session is fo
+r you,\nthe applicant, to provide a sample of your\t\neffective teach
+ing skills.</tag>";
$text =~ s/\s+/ /g; # convert white space to a single space
print $text;
[download]

The print statement is just there to show what's taken place.
edited to match the given example...
Of course, this still leaves a space between the tag and the text... dpuu and Ovid both give better ways of doing it... but I wasn't paying attention.