When using the speed() function of the turtle module under Mac OS X, 
it has no effect : the turtle always draws lines with the same speed.

An easy fix is to replace line 553 of the turtle.py file 
by "sleep(self._delay / 1000.0)", however I don't know if it is the 
best solution.

turtle.py was replaced by a new module in r63929 .
I can't reproduce this bug with this revision, so it seems to be fixed.
using: os/x 10.5.3 intel.

I wrote a small python program to test turtle speed in OSX. I tested
with trunk and py3k branch.

The string input works differently with 2.5, 2.6 and 3.0. The turtle is
slower in 2.5 and almost the same speed in 2.6 and 3.0.

Here are my test results:

david-kwasts-macbook:turtle davidkwast$ ../python_3k/python speedy.py 
0:00:04.640639
0:00:02.031436
david-kwasts-macbook:turtle davidkwast$ ../python_trunk/python speedy.py 
0:00:04.598181
0:00:02.048452
david-kwasts-macbook:turtle davidkwast$ python speedy.py 
(Python version < 2.6 don't support int in speed funtion)
0:00:18.343453

Although turtle.py lives inside the tkinter package, this doesn't seem
to be related to tkinter at all. I've set the "no selection" option for
the Components now.

I am attaching a simpler and hopefully more revealing test, speed_test.py.  This test repeatedly draws a full circle at various speeds and prints the time spent.  Here is the result:

# python3.1 speed_test.py
         0: 0.03
         1: 6.61
         2: 4.32
         3: 3.78
         4: 3.23
         5: 3.21
         6: 2.65
         7: 2.72
         8: 2.66
         9: 2.86
        10: 2.67

Note that time decreases as speed changes from 1 to 4 as expected, but then changes unpredictably as speed changes from 5 to 10.

I am attaching another test that demonstrates that the speed of the turtle is different when it draws a straight line and a circle.

The output shows the time it takes to draw a line and a circle of the same length at various speed settings.

$ python3 speed_test2.py
         0: 0.01 0.02
         1: 0.96 2.25
         2: 0.67 2.24
         3: 0.32 1.81
         4: 0.25 1.39
         5: 0.27 1.89
         6: 0.15 1.44
         7: 0.12 1.53
         8: 0.10 1.69
         9: 0.10 1.73
        10: 0.08 1.64