Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
One of the nice things about Microsoft products is that they have a lot of prefab goodies. OpenOffice.org is a little more of a from-scratch situation. But you have much more flexibility, and you can still do a lot of great stuff. It's not easy, at least not using this approach, to add borders all around, but you can do it in the top and bottom.
Step 1: Add graphics to the gallery.
You can find lots of great graphics on the Internet by googling for "free clip art." For the purposes of borders, keep an eye out for graphics that are small, i.e. under an inch by an inch, and also that have some white space around them.