Can I change my "hold music" to play something nicer or a promotional announcement instead?
The short answer is yes. You can even select multiple files that get randomly selected. The tricky thing is licensing. See this article for more info.
There are a number of royalty-free and public domain music on hold sites out there - a Google search will give you more than you cared to wade through
What you'll need to do is get us the audio files for what you want to play on hold, and we can put it in.