a buddy bought an olympus that is water and shock proof. we've taken it rafting, hiking some of the AT and kayaking. it has been submerged and dropped from at least 4 feet. i will see if i can dig out some shots for samples of quality.
here is a link:
http://www.olympusamerica.com/cpg_se...digital_sw.asp
i doubt a little sweat and a drop while riding would harm it.