I started running with ferocity in the beginning of 2009. I got shin-splints probably due to over-use.
It’s taken months for them to heal, even though a friend of mine, who is an experienced runner thought it would take only a few weeks.
I went to a physical therapist who says it takes a different amount of time to heal on different people.
Rest, ice and massage them if they are really bad. Don’t massage the bone, only the muscles around it. This will help get blood circulating through your legs.
Once they have healed enough that they aren’t painful, just to walk, try some other things.
1) Walk on the treadmill. Start out 5 minutes and stop, even if you feel like you can do more. (otherwise you will feel the shin-splints the following day). Work up to 10 minutes. Then 20. Do not run. When you can do 20 minutes, change the ramp settings to an incline. Again wait. After that, alternate walk-run.
2) Do lower leg exercises such as squats and walking lunges to strengthen your legs.
3) Make sure you stretch every day, even when you aren’t are exercising. Nothing helped more than stretching frequently.
4) Start biking. I was doing spin with very little resistance. I notice my healing process accelerate with this.
HTH.