Doing what you want is usually easier with a bind because you can trick it to activate twice in case the target doesn't catch in time.. but here is a macro version to target your specific friend and give him SB:
"targetname NAME$$powexecname Speed Boost"
As mentioned, if the target doesn't catch in time, you might have to hit it twice.
The bind version to avoid having to double-tap would be:
/bind KEY "+$$targetname NAME$$powexecname Speed Boost"
Those wont automatically switch back to the nearest foe though, but IF it somehow works smoothly and correctly for you with the targeting, you could try:
"targetname NAME$$powexecname Speed Boost$$targetenemynext"
YMMV on the timing and reliability. Good luck!
Edit:
I actually just tested that last command and it worked almost flawlessly for me (as long as a foe was already targeted). The SB went directly to the assigned name even though the targeting goes so fast that you never even see the target leave the enemy. Seems like this would be pretty sweet for specific duo circumstances. I'm not sure why it only works perfect if you have an enemy targeted, but a quick double-tap in other scenarios should clear it up. I hope you have a similar experience with it. 
Hello I am trying to create a Macro for Speed Boost, to target my friend that I duo with. I have never created a macro before in City of Heroes, so I am kind of new to this aspect.
What I would like for the macro to do is to target nearest Ally and then cast speed boost and then maybe go back to nearest enemy. Is there a command for someone you are grouping with and not just the generic friend?? He will have pets eventually and I would like for it to avoid them.
I tried messing with it in game and can kind of get part of it to work. So I currently have a Macro Power on the tray and if someone can tell me how to type it on that line when I go to edit that would be great.
Thanks for the help