Here is a running log (via Google Docs) of my personal best solve times. Many of the dates are hyperlinked to blog posts about the solve.
As of the end of May 2012 — after almost exactly six months of cubing — here is what my progress looked like:
The sharp quick drop followed by a long tail is really clear evidence of the steep learning curve. That phenomenon is also evident in this more narrow data set of my progress after starting to migrate seriatim away from Beginner’s Method (with the last drop after learning more OLLs/PLLs):