Question : uninstall 2008 sql server

I need to install 2008 express sql server  (mssmse 2005 )and I have sql 2005 express installed.
1)Do I need to uninstall 2005 express and mssmse
2)To install 2008 I do what after downloading 2 exe's with mssmse 2008

Answer : uninstall 2008 sql server

look at my blog link for more clear picture.

http://www.sqlhub.com/2009/05/instances-of-sql-server-run-multiple.html