Windows

Try the Ubuntu Forums for support.

Typical Ubuntu installations use Gparted to first shrink the Windows partition to free drive space for the Linux installation. Then Gparted lets you set the linux partition size, create a swap partition, and then you're ready to install. A good Ubuntu installer, like Cannonical, does all this for you automatically. BUT, you should always assume your data could get lost and FIRST create backups of anything important, just in case. If your netbook boots from USB, then I recommend you first creat a bootable USB version to test drive your OS candidate before you go all the way. There are usually instructions for doing that where you get your OS download or ask at the Ubuntu forum. You may even find others there who have done what you're doing on the same hardware already. It's easier than it reads here, but you have to be ready and willing to experiment a bit and learn the linux ways. Basically, any good linux distro will coach you through the installation and try like **** to let you keep you existing OS on an alternately bootable partition. Puppy linux is another low overhead version that should run well on netbooks too.