Some people find it useful to have SQL Express be the database for small ESX deployments -- < 5 hosts, < 50 VMs.

SQL Express doesn't have an agent to run jobs like regular SQL Server.

These tools help with scheduling common SQL tasks, and they probably can schedule regularly running scripts, such as the ones listed on vmware-land.com for cleaning out old data.

SQL Scheduler: http://www.lazycoding.com/products.aspx

ExpressMaint: http://codeplex.com/expressmaint

SQL "Agent": http://www.codeproject.com/KB/database/SQLAgent.aspx

I have successfully used ExpressMaint on one SQL Express installation with Task Scheduler.
After some practice to get the batch files' command lines right, it has worked well.
I have not tried the other ones.

HTH Tom