Step 1: Shafts
The first thing you'll need are some bamboo shafts. These are available at Lowe's (or other big box stores) as garden stakes. I prefer Lowe's simply because they sell them individually and I can pick through and get the best.
When selecting them, look for reasonabley straight 4 foot stakes about 3/8ths inches in diameter. They should still have a shiny yellow appearance, if they are faded and grey, pass them up.
Step 2: Straighten the shafts
The bends can be removed by heating the bamboo until pliable and bending in the opposite direction. The shaft can then be locked by blowing on the bamboo to cool it.
The inter-nodes should be straightened first, followed by the nodes.
Step 3: Prep the shafts
Cut an inch or so off the fat end of the shaft, then measure your draw length plus 2 inches and cut the shaft to length.
Afterwords, use a belt sander or disk sander to smooth down the nodes.
The open pith of the fat end of the shaft needs to be filled, a bamboo skewer dipped in wood glue can be inserted and left to dry.
Finally, lightly sand the entire shaft.
Now's a good time to straighten the shafts again. Practice makes perfect.