Getting Ubuntu 8.04 What should i expect

I think you should find out more before you install Ubuntu.

Ubuntu is another operating system, but it's different from Windows. You will experience similarities and you will experience things that are quite different.

Read more about it and fiddle around with open source applications before you make the leap. Most of your equipment will work out of the box, but some of it might not. Be prepared to learn more and be prepared for a great community of Ubuntu users. :)

Additionally, you might want to spend some time on the wiki https://help.ubuntu.com/. And when you get the CD you can run it in "live" mode which means you are not making any changes to the computer but running the operating system from the CD and in memory. When you reboot without the CD everything will be as it was.

Ubuntu is easy to use, but if all you know is windows then you will be frustrated as things are different. It would be like moving to a Mac. Macs are very easy to use too but different from windows. However, they are all computer operating systems so if you let go of the "windows way" and focus on doing the task the way that seems logical for the given OS then things become easier. You will still want to read up on a bit on the basic of navigating in a Linux environment.

About the delivery time, if you ordered the Live CD for free, it usually takes from 4 to 6 weeks, depending on where you live.

And if you want to keep a little Windows style Linux, I suggest you to check out Kubuntu, a branch of Ubuntu using KDE, whose interface is similar to Windows'.