I've been doing sort of a modified jelqing practice for several months now - you can read the details
on my blog (including several additional entries beyond the one linked) - and gotten good results.
Not with an actual increase in overall size, but with the "average" size on a daily basis. What I've found is that regular penis massage opens up the blood reservoirs, and stretches the anatomy so it relaxes, allowing me to hang freer than I was before starting this.
My erections seem to be harder, and more at the max I experienced years ago when I was in my sexual prime. So, it's been a positive practice for me.