i need to tap into a 4" cast iron pipe to install my drain for my washer. i need to know if there is a saddle or ? to make this possible. if i could drill a hole into the cast pipe to accept my washer drain line and insure it stays in place that would be great with the least amount of hassle. any thoughts ?

not the way a real plumber would do it but it can be done.
you also need to think about a vent for that trap.

I doubt that you would be able to find a saddle that would work, and there is more to installing the drain PROPERLY than just drilling a hole in the pipe.

I think it would be much easier to just cut out a section of cast iron pipe and insert a no hub cast iron wye with shielded couplings on each side,

If a saddle wye is used like one from Fernco I assume you need to drill a hole in the pipe that is not round but oval in order to be the same size as the branch comes in at an angle that would be really difficult to do, or you would risk having a constricted connection that would impede flow and cause headaches if you ever need to snake it?

Not to mention that by the time you cut the hole in the pipe, you could have rented a pair of chain snaps from somewhere, installed the new connection, and been done and bragging about how smoothly everything went instead of doing it improperly for 3 hours. Most tool rental places have chain snaps, and a 4 hour rental is usually less than a meal for 2 at the golden arches.