I just created a Jamaica Plain focused hiking/walking meetup group.  For those who are unfamiliar with the meetup concept, participation is free and it's a way for people with common interests to do stuff.  Here's the description:

This meetup group is for Jamaica Plain residents who like to walk and hike. Since we are all coming from the same place, coordinating local walks/hikes should be relatively easy. This group may also end up being a relaxed way to meet some of your neighbors.

A few points:

• Although some walks will be in or around JP, not all will be, but they will be convenient for people coming from JP.
• I generally will not institute RSVP limits, nor do I really care about no shows. You will have the flexibility to add an event from this group to your calendar and then either show or not based on what else comes up in your life.  
• Expect that the hikes/walks in this group will be at least at a moderate (to faster) pace, and so please be in relatively good shape and able to enjoy some exertion.

Feel free to join here:  http://www.meetup.com/JPHike/

Nick