Is samba installed?

I am new to Linux. Interested in making my home XP-pro, desktop server, allow me to print from my other desktop that runs Unbuntu 10.04, I looked in applic>ubuntu software center>installed software, and did not see Samba. So I downloaded it with bash: sudo apt-get install samba. Went back to "installed software" again, still not listed. So I went to applic>accessories>search for files, typed in samba, and there are many samba files dated 4/9/10, the day I downloaded the updated Ubuntu. Also in that folder are samba files I downloaded Aug 7.

It appears neither is installed? If I open the folder 'sys-config-samba-desktop'(dated 4/9/10), there is an install button. None of the other files/folders. if opened, seem to offer the install button.

Is Samba installed or running in the background? Do I need to uninstall the download from Aug. 7? If so, how do I do the uninstall?

I have have a separate printer connected & working with the Linux desktop. Just interested in learning this stuff.
Thank you,
Michael Leath