Something like this would work well for running, it straps on your arm.
You might have to cut out some of the plastic face so you can touch the actual screen on the droid since its capacitive, but it would probably work.
Can be found here if your interested...
Belkin Universal Cell Phone & MP3 Case w/ Armband F8M005-SML - Motorola DROID Cases & Holsters
I run with the Armpocket Sport 20 -- and I Love it!
It carrys my phone/music, ID, keys, and GU; has 3 pockets on the inside and a great locking audio port on the bottom so my ear-jack doesn't disconnect. I have small arms and all the other cheap armbands slipped right off. This actually comes in a small strap length with a vented, moisture-wicking strap that fits perfectly! Another reason it doesn't slip is the memory foam really contours to the shape of my arm, so I can really load this thing up and it won't slip.
Best of all it has a touch/heat sensitive screen that I can run my apps "on the move,"
and the double-pull zippers are super easy to get stuff out while running. I tried other cheap armbands, belts and various shorts/sweats with pockets and they all bounced and left sweat marks... not to mention bruises -- sweat and $300 smartphones... not a good combination.
The Armpocket is the gift I'm giving to all my running buds for Christmas. I recommend you check it out at www.armpocket.com. Happy Droid Running!
I'm going to try this armband/headset combination once santa makes his delivery
Armband: Amazon.com: Tune Belt Sport Armband for HTC EVO 4G, Droid Incredible & more (fits larger smartphones and iPhones in protective cases like iPhone 4 in Bumper case): Electronics
bluetooth stereo Headset: Amazon.com: Motorola S9-HD Bluetooth MOTOROKR/MOTOACTIV Stereo Headset (Gloss Black): Cell Phones & Accessories
I have an arm strap made of neoprene with a velcro strap. I think it was made for the iPod or iPhone, but my Droid fits in snugly. I think the manufacturer is Body Glove. I use it at the gym and on my bicycle, and I've never had any issue.
Rooted D1, ChevyNo1 1.1ghz mdV kernel, MIUI 1.6.10 ROM. Google voice/Groove IP home phone.
Droid Incredible 2, Tiamat 1.1.5 kernel, Liquid 3.1 ROM. So far, so good!