One of the bushings on my Mazda5 was leaking at 50k miles, I replaced the whole arm. I don't think you can just get the bushing. It took a couple of hours in my driveway. On my car you have to undo the rear motor mount and rock the engine a little to get one of the bolts out. Search my user...
Here's a follow up:
I bought a Mazda replacement LCA with the bushings and ball joint and installed it yesterday. It was about a 2 1/2 hour job, including finding my tools and cleaning up. This was the right side, so I had to remove the lower back motor mount bolt and rock the engine forward...
I just noticed that my front right control arm had oil under the big bushing. I have 50k miles on my Mazda5. Is this a common failure, or am I just unlucky? It looks pretty easy to replace the control arm. Any hints?