This page about the K-On! manga has some preview pages:
http://www.dokidokivisual.com/comics...st.php?cid=200
The second manga volume will be released on February 26, 2009.
Wallpaper:
ETA: Cover for the second manga volume and some preview pages from the publisher:
http://www.dokidokivisual.com/comics...st.php?cid=278