Yes, I've heard of a T-28 being used quite a few times. You need to decide whether the canopy is clean and distortion free enough to shoot through, or go with the canopy open. Open obviously limits you to fairly low levels. If the canopy is open, you'll need a good head set connected to both the intercom system in the T-28 (so that you can hear and speak to your pilot) and connected to the aircraft r/t (to talk to the pilots of the subject). You'll need to check into this respect the aircraft r/t - is a none-radio licenced user allowed to transmit on aviation frequencies (in the UK this would be illegal). As you're in the US, you can look at the possibility of using 123.45 for air-to-air communications (also illegal in the UK!).
Other than that, plan, plan, plan, and allow plenty of time for a thorough briefing including yourself, both sets of pilots. As I said, this brief will need to cover shoot expectations, procedures (particularly safety), communications, positioning. You'll need to consider where the sun is going to be, and the empty airspace you have available. Remember with a Lear you'll be batting along quite a bit, but even with a T-28 you still need to look at the numbers as I'd imagine the Lear will be somewhat faster unless its pilots are pushing the envolope a bit at the bottom end - I may have to accept passes rather than a period in formation.
As to lenses (Andi asked), just think about what sort of lens you'd use on the ground. A Lear isn't that big and if the relative speeds work out more than a few knots different, the pilots won't be getting that near. A long lens is a must, 300mm may do or it may not, and it'd be difficult to make any definitive decision on that until you've had a chance to discuss the trip with the pilots. Whatever you decide on lenses, remember that changing in the air isn't going to be easy in a small rear cockpit with an open canopy.