I have several photo tutorials on How to Build Boffers on my website:

How to Make a Sword

How to Make a Shield

And I need to update these pages, because Hang 'em High Fabrics stopped carrying 0.602" kite spar, which is used in making two-handed weapons. For the core of your weapons, I recommend Goodwinds Kites -- they're used to LARPers placing orders!

For two-handed weapons, use 0.602" fiberglass tubing.
For one-handed long clubs, maces, and swords for stronger folk use 0.505" fiberglass tubing.
For short swords or swords for ladies and men who can't bench-press their own weight, I suggest 0.405" fiberglass tubing.