crank...crank...crank and no start!

I have a 96 monte carlo, just recently it started giving me problems (last 2 days) it will not start...i have to sit and crank it and crank it for 5-10 minutes...trying for a few seconds then turning it of for a little then trying again and then finally it will start, but barely. However once it is running it stays running and runs fine....

where do I even start to find this problem?

Check fuel pressure for starters.