Convert a mySQL DB to version 5
1. Backup your mySQL 4 database in phpMyAdmin
2. Make a new mySQL 5 database and import your mySQL4 database into it by using  phpMyAdmin.
3. Edit your wp-config.php which is found in the root folder of WordPress by changing the old database name, username, password, and the host name with the new database name, username, password and hostname.
4.Save the file and upload the file to the root folder of word press.
5. you are done.
If you use 1and1 as a webhost, this link ( http://www.faq.1and1.com/scripting_languages_supported/mysql_database/10.html ) is useful.
I admire the valuable information you offer in your articles. I will bookmark your blog and have my children check up here often. I am quite sure they will learn lots of new stuff here than anybody else!