I need to know if the ESI ESU 1808 soundcard will work on my ubuntu, before I buy it. I've tried to google some answer, but could not find anything relevant.
It would appear that the sound card is not compatible with Ubuntu (source: here). However that post is from October, 2007 a lot may have changed. Have you thought about contacting the manufacturer/retailer directly? Most offer some form of pre-sales support. Conversely you may want to get an Asus Xonar instead which are known to work very will with linux (and are great sound cards).