DoctorC - 1:49 pm on Aug 23, 2011 (gmt 0)
A copyright is deemed to be valid for any published work. The use of the (c) 2011 Some Company, Ltd. is desireable. But you do not need to file in the USA and maybe it is similar in other countries like the UK? The filing of the copyright form puts it on record and acts as proof (not definitive proof) of ownership, which is desireable in a court of law. Sort of "My proof is better than your proof."