Hello guys,
Some of you may know about this feature.  You can have outlook express sort 
your messages by conversation.  This is very handy when you want to either 
read or delete messages on a given topic.
If, for example, you're not interested in reading 20 messages on a 
computer-related topic, you can just delete all the messages by deleting the 
first one in the topic.
You use the right and left arrow to expand / collapse the topic.

To enable the feature go into the view menu; then custom view and arrow down 
to the "group by conversation" item.

hth
Chris