Well I was curious and downloaded. After downloading it updated the channel listing which took about a minute and a half. You then have to put in your name, email and promo code (if you have one). Then your 24 hr trial begins.
You have 6 genres to choose from: pop, hits and dance; rock; country; decades; jazz and classical; and comedy.
In pop the channels are: Top 20 on 20; The City; XM Hitlist; Flight 26; and XM Chill.
In rock: Lucy; Top Tracks; Starbuck's XM Cafe; Ethel; and XMU.
In decades: The 60's; The 70's; The 80's; and The 90's.
In country: Highway 16 and US Country.
In jazz: Watercolors.
In comedy: The Virus and XM Comedy.
"If men define situations as real, they are real in their consequences." - W.I. Thomas