As soon as the SHDH is announced:

All places where it’s announced link to a central wiki page for lightning talks
That wiki page has a contact email for the lightning talks organizer and a list of who wants to do talks
That wiki page has a list of things for presenters to know:

You get 5 minutes
Your talk has to be approved by <organizer> (It probably will)
Email <organizer> at <organizer email> or add it to the list above and I'll email you
You have to present from the presenter’s laptop (because swapping laptops is a bad experience for the audience)
Introduce yourself at the beginning of your talk
A good (but not required) presentation format is:

After the talks are over, stay up by the screen for five or ten minutes. People will want to talk to you

Leading up to and during SHDH:

When people contact you or add themselves to the list of presentations, ask them for presentation materials.
Try to help people with boring/recruiting talks by giving them better topics they might be able to speak about
Make sure their slides are a format you can display
Turn away talks that won’t fit into 5 minutes if you can’t get them to trim them down to something that will work
Try to keep it to about 10 talks. If there are already 12 or so signups, you may have to tell people "sorry we're full" unless their talk is awesome. This is a great problem to have
Get something that can display powerpoint and openoffice slides on the presentation laptop
Make sure the presentation laptop is setup for dvorak and qwerty (presenters may need to switch between them)
Add them to the wiki page if they contacted you by email; email them if they added themselves to the wiki page
Link their presentation materials from the wiki page where possible

When you get to SHDH:

Is there an AV guy?
Where’s the projector?
Where’s the screen?
Where can we put those to maximize the audience? Put this information on the wiki
What time are talks? Is there food to schedule around? Put this information on the wiki
Is there a sponsor? Do they expect a time slot during the talks? Who’s our contact?
Are we taking donations? If so, where’s the donation box to hand around during the talks?
Email the presenters to tell them where and when to meet (at the screen, a half hour before the talks, to make sure everything works)
Go over the format with them
Order the presentations so that they alternate supertechy//nontechy, serious//fun, etc (do this on the wiki page)

Half an hour before the talks:

Make sure the laptop plugs into the projector and a mic works if it’s available
Explain to the presenters that they should stay up afterwards
Tell them the order they’re presenting in, make sure everyone knows who they’re after
Tell them that you’ll hold up two fingers when two minutes are left, and one finger when one minute is left
Announce the talks throughout devhouse
If the audience is huge or the venue is somehow special, have each presenter do a dry run through their presentation materials to make sure everything works as expected

During the talks:

Thank the sponsor up front, say something to pump the crowd up
Call up the first presenter
Remind each presenter to introduce themselves, to eat the microphone where necessary, and to watch for the two and one minute marks
Load up their presentation materials for them (avoids them flubbing it in front of the audience)
Time them with your phone. When two minutes are left, hold up two fingers until they make eye contact. When one minute is left, hold up one finger until they make eye contact.
Don’t interrupt them when their time is up. They’ll wrap it up.
Thank everyone for coming, and ask the audience for a round of applause for the presenters
Tell the audience that the presenters will be up front for five or ten minutes if they want to ask questions

After talks:

Maybe try:

Some useful blocks of text to paste into emails:

Thanks for giving a talk! You're making devhouse better.
Do you have slides or presentation materials I can look at? It's best if they're somewhere online so I can link them from the lightning talks schedule. It makes the talks run more smoothly and lets people look at the slides on their own time outside the talks. Don't wait until the last minute to give me slides! Everyone always does this, and it delays the talks by 15 minutes while I get everyone's last minute slides ready one at a time.
Things to know about giving a talk:

You get 5 minutes
You have to present from my laptop because swapping laptops is a bad experience for the audience
Introduce yourself at the beginning of your talk
After the talks are over, stay up by the screen for five or ten minutes. People will want to talk to you

lightning talks best practices