The installation process for Ubuntu is pretty simply. Get yourself a CD, either by burning yourself an ISO downloaded from the main site, or ordering one online.
Reboot your computer with the CD in the drive, it should boot off of the CD, and it'll give some options on how to boot. and by default it'll go into the LiveCD. Once the LiveCD is loaded, you're now running Ubuntu on your computer without changing anything on your harddrive.
To install, you simply go to 'Install' on the desktop, and the process from there is extremely straightforward.
Well, if you want to get your hands dirty with some initial work to get things the way you like,
You don't really have to get down-'n-dirty at all, unless you're doing some core optimization. If you're using the GNOME window manager (the default flavor of Ubuntu), configuring the basics should be easy.
Maintenance, on the other hand, is up to the user.
If you don't organize your files, try messing with the base directory structure, install ungodly amounts of applications and never clean up afterwards, then yes, maintenance will be a hassle.
However, if you keep to installing applications via the package mananger and don't try making any changes to your root system (unless you know exactly what you're doing), it should be extremely easy.