Well, I got something working, but my current implementation is taking about 6 seconds to do a fill for the whole screen (480x854 on a Moto Droid currently)
I have some ideas about how to speed it up a bit. If anyone is interested about this or my implementation, ask away or PM me.
Here is the pseudo code I used to make my implementation, taken from Flood Fill
Flood-fill (node, target-color, replacement-color):
1. Set Q to the empty queue.
2. If the color of node is not equal to target-color, return.
3. Add node to Q.
4. For each element n of Q:
5. If the color of n is equal to target-color:
6. Set w and e equal to n.
7. Move w to the west until the color of the node to the west of w no longer matches target-color.
8. Move e to the east until the color of the node to the east of e no longer matches target-color.
9. Set the color of nodes between w and e to replacement-color.
10. For each node n between w and e:
11. If the color of the node to the north of n is target-color, add that node to Q.
If the color of the node to the south of n is target-color, add that node to Q.
12. Continue looping until Q is exhausted.