There are a lot of guides online if you search for how to set up KVM (which uses QEMU). Linux distros also provide documentation specific to their distro:

https://access.redhat.com/site/documentation/en-US/Red_Hat_E...

https://fedoraproject.org/wiki/Getting_started_with_virtuali...

https://help.ubuntu.com/community/KVM

If you need help, ask on #qemu on irc.oftc.net or #kvm on chat.freenode.net.

What distro are you most comfortable with? We run KVM on Debian in a few offices, with the VMs doing mail, web, and DNS. It's been about a year and it's been rock solid.