slightly offtopic/
anyone know of any ubuntu techies who would be able to assist me in having our windows based point of sale run on Ubuntu?
I would suggest giving WINE a try for this. The only problems you might face is if the POS software makes use of shared Windows DLL's but if you can work out which ones they are it is easy enough to include them (though this is probably a copyright infringement...)
Another option would be to run a VM instance of Windows... but I gather this will be a pointless exercise as your motivation for asking this question is more than likely a need to move away from a buggy, unstable, virus-prone spyware target of an OS...
On the plus side though is that using a Linux distro as your host OS you can "protect" your VM using a firewall (iptables) and antivirus (AVG) combination but yet again... why bother?
Question about ubuntu: If its released every 6 months, does it have a seamless upgrade system? or does one have to reload everything when going to the next version.
I think this has been answered but just to review, the upgrade/update (they're the same system : apt-get) process is simple to use. I have been running the same system for 2 years, initially starting with 6.06 Dapper Drake that I got posted to me using the shipit service
shipit.ubuntu.com and have been subsequently upgrading the OS ever since to the current 8.04 Hardy Heron with which I am immensely impressed (I just love the ability to preview a song just by hovering my mouse over the file)
Anybody still wondering if they should switch over
just stop wondering. Download/steal/borrow/get a copy shipped (FREE!) and install it. Its as simple as that.. (BTW Google is funding WINE development to seamlessly run the only real KILLER app in Windows, Photoshop

)