Yeay, my first week of speed training ever. (I did something remotely resembling speed work when I was last doing a running program 3 years ago, but not really).
After getting the advice of the intrepid elite runner Steve King (WBR team captain), I decided to do 1/2 mile repeats, and take it real easy this time. So, ~2 mile warmup to where 10:00 pace was comfortable, then 1/2 mile at 7MPH(~8:57 pace), 1/2 at 10:00 again, repeat the whole time. I think I extended the last one to .75 mile, and then spent the .25 mile cooling down to make an even 6 miles.
I felt really great after this run. My legs still hurt a bit from my 10-miler over the weekend, so this workout added to that a bit, but overall it was not a dificult run.