Cover art (not previews) for 2x04 songs up on Amazon!

River Deep, Mountain High (Tina Turner) - Mercedes & Santana.
http://www.amazon.com/River-Deep-Mountain-High-Version/dp/B0045NHSSA/ref=sr_1_1?ie=UTF8&qid=12860274

Lucky (Jason Mraz & Colbie Caillat) - Sam & Quinn.
http://www.amazon.com/Lucky-Glee-Cast-Version/dp/B0045NHVX2/ref=sr_1_2?ie=UTF8&qid=1286027489&sr=1-2

Le Jazz Hot (from Victor/Victoria) - Kurt.
http://www.amazon.com/Jazz-Hot-Glee-Cast-Version/dp/B0045NCFZG/ref=sr_1_3?ie=UTF8&qid=1286027489&sr=1-3

Don't Go Breaking My Heart (Elton John & Kiki Dee) - ?
http://www.amazon.com/Dont-Breaking-Heart-Glee-Version/dp/B0045NAJ4A/ref=sr_1_4?ie=UTF8&qid=1286027489&sr=1-4

Sing! - ?
http://www.amazon.com/Sing-Glee-Cast-Version/dp/B0045NHT5M/ref=sr_1_5?ie=UTF8&qid=1286027489&sr=1-5

Happy Days are Here Again/Get Happy (Barbra Streissand/Judy Garland) - ?
http://www.amazon.com/Happy-Days-Here-Again-Version/dp/B0045NDYJC/ref=sr_1_6?ie=UTF8&qid=1286027489&sr=1-6

via gleeclub