This is the sort of riddle that Google is good at solving:
http://www.google.com/search?q=16+Nov+2006,+31+Oct+2006,+29+Sep+2006,+21+Sep+2006,+12+Sep+2006,+17+Aug+2006,+09+Aug+2006,+01+Aug+2006,+29+June+2006,+27+June+2006,+23+May+2006,+11+May+2006,+17+Apr+2006,+03+Apr+2006,+13+Mar+2006,+01+Mar+2006,+14+Feb+2006,+10+Jan+2006,+3+Jan+2006&btnI="I'm Feeling Lucky

Terminal to the rescue!

You can un-rot13 by typing in the following:

echo "Gurl ner nyy qngrf ba juvpu Nccyr eryrnfrq Frphevg Hcqngrf guvf lrne." | tr "[n-za-mN-ZA-M]" "[a-mn-zA-MN-Z]"

The "tr" command allows you to "transpose" characters. In this case, it is matching each character to the thirteenth previous charactor Normally, it is used to convert upper to lower case, etc:

echo "$string" | tr "[a-z]" [A-Z]" #Convert to uppercase
echo "$string" | tr "[A-Z]" "[a-z]" #Convert to lowercase

You can also use it to ROT-13 text for you:

echo "$text" | tr "[a-mn-zA-MM-Z]" "[n-za-mN-ZA-M]"

For more information about the "tr" command type the following command:

$ man tr

That will display the "manpage" on the tr command.

Drive to the the nearest CPAN and install Crypt::Rot13 (I had to say "install AYRNIEU/Crypt-Rot13-0.6.tar.gz" in CPAN shell).

Then just do

$ perl -MCrypt::Rot13 -e '
$rot13 = Crypt::Rot13->new;
$rot13->charge(shift);
print $rot13->rot13' 'Gurl ner nyy qngrf ba juvpu Nccyr eryrnfrq Frphevgl Hcqngr f guvf lrne.'