One of the things that worries knitters most about knitting a sock from the toe up is making sure the bind off is stretchy enough. If you bind off too tightly, you may not be able to get the sock onto your foot!
The good news is that, even if you bind off too tightly, you can just rip out the bind off you started with and try again. But it helps to start with a bind off that's a little stretchier than the standard. Eileen Casey recommended the knit through the back loop method of getting a stretchier bind off, but my personal favorite is one known as Peggy's Stretchy Bind Off.
I learned about this one from the Socknitters.com website, but there are no pictures there, so here's a more graphic version.
It's a really easy method but it does require a setup row, so just work one round fewer of the ribbing than you need for length. On my sample I was working a knit 2, purl 2 ribbing, which means on the last round before the bind off I needed to do a knit 2, make 1, purl 2, make 1 around. Instead of the traditional make 1 I do a loop cast on.
If you were working with a knit 1, purl 1 ribbing on the last round you would do a knit 1, make 1, purl 1, make 1 around.