[whpalmer4]

Okay, it's not too difficult, you'll probably be able to do it without the assistance of your favorite two-year-old :-)

Launch OmniGraffle on the Mac
Open the Stencils window via Windows->Stencils (or command-0)
Open up the Maps folder and select the stencil you want to copy to the iPad
Click on the Gear menu at the top of the Stencil window and select Edit A Copy
You should now have a window with the stencil open as an OmniGraffle document

Select File->Save As... and choose a location to put the file where you'll be able to get to it easily
Save the file there (*)
Now you have a copy of the stencil file ready to transfer to your iPad

At this point, you have a couple of options. One is to mail the stencil file to yourself by dragging the file and dropping it on the Mail icon in the dock. Once you have sent it, go read the message on the iPad, tap the icon for the attachment, and select "Open in OmniGraffle" to get it into OmniGraffle on the iPad. The other straightforward option is to use iTunes. Cable up your iPad to the Mac, launch iTunes, and select the iPad in the list of sources on the left side of the window. Now click where it says Apps above the description of your iPad near the top center of the window. Scroll this window down until you get to the bottom, where it says "File Sharing" and there is a list of apps on the left and a list of documents on the right. Select OmniGraffle on the left, click the Add... button, choose the file that you saved earlier, and click Open.

At this point you should have the stencil installed on the iPad. Wasn't too difficult, was it?

(*) I'm not quite sure how you do this under Lion, probably with the File->Duplicate command, but having not done it, I can't give you tested instructions