If you dont have any other fittings, spend the money and get the proper fittings to do so. You tap the fuel source from the feedline off the fuel filter to your fuel rail. You can buy a simple t barb if you must but flare fittings would be my way of doing it. Unless of course you have an after market rail when in most cases it has a closed fitting off the return end that you can run a feedline from.
If i were you i would find somebody who has done them before, because in most cases its not something you want to mess around with blind.