Upgrade advice

[Dean Mumby]

I am currently running ubuntu ltsp 7.04 I was wondering what the best 
approach might be to get to ubuntu 8.04
1. Should I upgrade to 7.10 using the upgrade manager and then upgrade 
to 8.04 using the same or
2. Should I somehow upgrade to 8.04 using the alternate cd etc or
3.???

Any suggestions , this is a production machine in use everyday , I want 
to try avoid any downtime.

Regards
Dean