About 30 minutes there in the morning, depending on which gate you use at Jebel Ali. If you are entering via gate 5, that can add another 10 minutes to the journey.
Back home again can take anywhere from 40 minutes to 1.5 hours. The road clogs up at Mall of the Emirates and is often bumper to bumper all the way to Sharjah from there.
Thanks Knight The map (albeit pretty poor) that I have has gate 7, 4 and 3 on it. The site I'm going to is near Emirates Chemical. Anyone know when the metro stations will open in Jebel Ali? and is the Business bay open now?