Another thing that's never mentioned in regards to illegals and work is that not only will they work for less, but their sheer numbers that keep increasing drive those wages down even further. When labor pools expand, the wages drop. More illegals means lower wages for all illegals.
Good point. They are also not covered by the miriad of paperwork costs usually associated with permanent employment. So that cost is saved.
DK
http://www.cis.org/articles/2004/back504.html
This study is pretty good done in May this year.