Steve,
Well... 'kinda' both. You have to apply and the registar will review your application. Assuming that it meets the criterion, you will receive the copyright.
Although filing with the eCO form both less expensive and quicker, you will probably have to use the CO form (as you have to send in the first 50 pages on your code and instructions - the copyright will cover both your user's manual and the program). The forms can be somewhat confusing and the registers are looking for certain 'key words'. The Nolo book(s) will greatly assist in navigating you through this process and actually make the process quite easy. If your library does not have the Stephen Fishman book(s) (either of the first two I mentioned in my original reply), by a copy off of Half.com - it is a very good investment and HUGE timesaver plus it will clearly address any questions that are bound to arise.
You are right about 'licensing' rather than 'selling'; however, it does not sound as if this is your first rodeo.
http://www.copyright.gov/forms/
http://www.copyright.gov/circs/circ61.pdf