IE vs Mozilla Firefox column issues

Please have a look at the following screenshots:

My blog in Internet Explorer:
http://www.thisishamid.com/temp/ie.jpg

and
My blog in Mozilla Firefox
http://www.thisishamid.com/temp/firefox.jpg

And notice the difference for what the body concerns.
How can I fix this? Narrowcolumn? Widecolumn?
I have to add that it should be ‘something’ like how Firefox shows it..

I’m using WP 1.5.2
Thanks in advance,
Hamid