Is it an issue for artists to worry about? I don't know. When I dig in and research it, there are a bazillion different opinions on it.
From what I understand, the basis for the Bill is it allows for people to use older creative works when the copywrite holder has died (for 70 years past their death) or where the original holder cannot be found.
Film makers, musicians, etc. can not currently use this material, but the Orphan Works Bill would allow works to be used if the user can show that they made an attempt to find the copywrite owner.
I'm not going to attempt to convey the concerns of the art public because I don't fully understand but I have found some links. So if you are an artist trying to decipher it, read these and decide for yourself:
There is a lively debate happening here: http://www.publicknowledge.org/node/392
If you want to send letters to your congresspeople expressing your concerns, go here:
And six misconceptions about Orphan Works: http://maradydd.livejournal.com/374886.html