I would say that the closest thing in Star Wars would be what we see in AotC with the troops landing in attack gunships...
But if you're intent on using the whole paratrooper-esque technique, you could conceivably have the troops use some sort of repulsorlift pack that slows their descent. I don't think it would make sense to go with an orbital drop, though. If the anti-air cannons are good enough to cause problems for the dropships, they'd be good enough to shred apart any sort of orbital drop, unless the soldiers were able to fly in on something akin to the basilisk droids Emon mentioned, but even then, ground defenses would take a significant chunk out of the rebel forces, and from what you've described, it doesn't sound like the rebels could afford to spend that much on that many vehicles that will probably be shot down anyway (nor does it sound like they'd have the time to pull enough of those together, if this is a rushed attack). The Mandalorians did it because they were crazy and suicidal; I don't think it would make much sense for the rebels to emulate the same tactic.
In the end, though, dropping via parachute isn't too crazy for star wars. After all, slughtrowers are still popular weapons, and a lot of cultures still use unpowered swords and the like. I think it's important to keep in mind that star wars isn't so much a futuristic sci-fi universe as much as it is a fantasy setting with technology.
Ultimately, though, what I think would be cool, would be something akin to AotC (like I mentioned above), with several dropships speeding past the Imperial defenses and landing the troops inside enemy territory. Or even have the dropships stay in flight, stopping long enough for the infantry to rapell down to the ground before flying off. I'm thinking like the intro sequence for HL: OpFor, 'cept... with ships and blasters.
But again, if the whole paratrooper idea is something you really want to keep, there are a lot of ways you could work it out and have it still fit with the Star Wars feel.
Moo.