Qais Fulton of Destructoid says,
"...we've got next week's rock offerings a couple days early. On July 8th (the 10th for you PSTriple-ites) Harmonix is serving up a delicious rock stew featuring the Red Hot Chili Pepper tracks "Snow" and "Tell Me Baby", as well as Rush tracks "Closer to the Heart" and "Working Man". Each track is $1.99 (160 Microsoft points) and all tracks are masters.
That's right, Harmonix has managed to wrangle an master version of "Working Man". Not only a master, but a master with an alternate solo that has yet to be released publicly..."
Rock Band continues to bring on the awesome DLC, and it's all going to be playable on Rock Band 2!