The boingy boingy yarn is Cascade Yarns' Fixation. It hugs your feet, and also doesn't droop after wearing for a while. If you're new to socks, I recommend you use four needles to hold the stitches, and not three. You get a "run" in the socks at the spaces between needles when there are only three.
Also, if this is your first time, I highly recommend you use a contrasting strand of yarn and run it forward and back between a set of stitches to make it easier to count the rows you've worked. You may even use different colors for the rib and upper part, the gusset, and the foot sections, so when you are ready to do the second sock, you can ensure you've got the correct number of rows in each section.