Depending on the age of the floor, you may want to simply remove the linoleum and the underlayment at the same time; NOT just the linoleum.
The glue may be hazardous. You don't want to use a saw in any part of the removal process because this will heat up the glue and do nothing but make the asbestos airborne (assuming there's asbestos in the glue). There is a post on the main page that you can click on (the link is Removing Tile that goes beyond the 'tile' aspect and a little into Real Estate Disclosure and Non-friable Asbestos Removal. It's worth a look.) In my opinion, it's best to remove the tile, glue, and underlayment in one shot. By installing over it, you may have 'problems' later. Just my $.02.