Switching from heavy trainers to flats

The way I did it was starting to run all my doubles in flats. Then as my old shoes started to wear out, I wore flats on a couple of one hour runs a week. I took a year to totally transition, but I'm pretty prone to overuse injuries.

I'm not running doubles right now...

I used to train in the Asics 11xx series. It took me 1 year to transition to 100% running in flats. I now run in the Asics Hyperspeed 2 & 3, and Adizero PR (when I can find a good price).

My method: First I switched to the Asics Speedstar 2s, (basically DS trainers but neutral). I started by doing all runs < 5 miles in them. Once I could do that without any calf soreness (you will have calf soreness), I did all runs < 8 miles in them, then 10, then all runs. I went through 2 pairs in 6 months, then I did the same thing when transitioning from the Speedstars to the Hyperspeeds. I've been running 100% in Hyperspeeds for 6 months now. Last time I was injured was about 6 months before I switched to the Speedstars (knock on wood).

This was a very conservative approach, but at the same time I was doing this, I was also changing my footstrike from heel striking to fore/midfoot striking. I just forced myself to fore/midfoot strike on all runs in the lighter shoe I was transitioning into, until I switched completely. It now feels natural to fore/midfoot strike, and the only time I land on my heel is on steep downhills, and sometimes I'll land on my heel a few times on really uneven trails or grass. The transition can probably be made safely in less time, but why risk it? There's no rush. Listen to your body.

I have already gotten used to running on my midfoot/forefoot (process that involved long injury)... but I still plan on transitioning cautiously.

well the basic idea still applies. Mostly you just don't want to suddenly be doing a lot of training in flats because you might outpace your body's ability to adapt.

If your really sick of heavy trainers try to transition into Vibram Five Fingers. I'm the same way hating heavy shoes. To transition you would need to walk in them often. Good luck I'm in the same boat.