1. create guides where you want the center of the circle to be

2. use the circle marquee tool. draw from the center point holding option and shift. this draws from center and constrains it to a circle.

3. fill with black or whatever color you want the outer ring to be.

4. select->modify->contract enter the number of pixels you want the width of the outer circle to be. probably somewhere between 5 and 15 depending on the resolution of your file.

5. select->modify->smooth this makes sure the circle stays perfectly round. sometimes photoshop does weird things. 3 - 5 pixels should do the trick.

6. create a new layer and fill selection with white or whatever color you want

7. select->modify->contract enter the number of pixels you want the width of the inner circle to be. probably somewhere between 40 and 65.

8. select->modify->smooth this makes sure the circle stays perfectly round. sometimes photoshop does weird things. 3 - 5 pixels should do the trick.

if you want to do a solid inner line, create a new layer and fill with black, then repeat steps 4 - 6. you can adjust each layer to give them texture or gradient fills, etc. and then merge the layers, delete the center white circle and place over your map.

if you want to do the dashed line, i'd say get illustrator cuz it takes all of 5 seconds. if that's not an option though, here's the photoshop way. (if anyone knows an easier method, i would love to hear it!)

1. keeping your selection active, create a new layer on top. you should have 3 total now.

2. switch to the pencil tool (click and hold on the brush tool and you'll see it, or press shift-b) i used a 20px tip

3. under brush options click "brush tip shape" and adjust the spacing to somewhere between 150 and 200%. you'll want to play with both the size of the tip and the spacing depending on the look you're going for.

4. click on the paths tab and at the bottom, click "make work path from active selection". it should be the left most active button.

5. now click the second button from the left in the paths tab, "stroke path with brush". this will draw a dotted line on the path you just made from the selection.

6. unless you want dots, here's the pain in the ass part: click the 3rd button in the paths tab "load path as selection".

7. select->modify->contract this might take an adjustment or two since you want to have the new selection cut off about a quarter of your dots. i used 3 pixels.

8. select->modify->smooth whatever value you had in there should be fine.

9. hit delete!

10. select->modify->expand for this i used 7 pixels. it should be double what you just contracted the selection by.

11. select->modify->smooth whatever value you had in there should be fine.

12. select->inverse invert the selection

13. hit delete! and there you go.. one dashed line.

it is a whole lot easier to dashed lines when they are straight by using a square brush tip, but with circles, this is the only way i could think of off the top of my head.
also, with the values i used, the dashed line is not as thick as the outer line. if you want a thicker dashed line, just use a bigger brush. the other option would be to expand your white circle on layer two or shrink the outer circle layer.

hope this helps! let me know if this makes no sense at all.