I have a 2000 Astro Van. When I first get on the freeway in the morning it has some hesitation for the first few miles. Replacing the fuel filter has not helped. Any ideas?

Wow, where to start?
There's an encylopedia's worth of information in this forum about this subject.
One thing that will help narrow the possibilities is if you post the mileage on the vehicle and the current state of maintenance, for example, has any basic tuneup been done on the engine? plugs, wires, distributor cap and rotor.
Any other symptoms, erratic gauge readings, engine running warmer than usual?
Since it wasn't in your post, I'm assuming the check engine light is not on.