Are there any inexpensive tools, web-sites or services you know of where one can see:
a) current implied volatility skew for an option chain
b) historic implied volatility skew
for a) consider http://www.samoasky.com - they have a free tool called optionsoracle which allows you to download option chains for most markets automatically, and plot a "volatility smile", which you can then filter out for expiry, calls/puts etc.
for b) I don't know any tool, but I did write one myself in C# and Zedgraph, which was a timer animated client side tool. You might want to check http://www.hoadley.net/options/options.htm for some applications that could ease the job for you.