Originally Posted by MHDTV

I haven't figured out how to fit LastFM widgets into my sig...

Originally Posted by Yac

You can include your last.fm chart using
[last.fm.charts=YOUR_CHART_STYLE]NAME_AT_LAST.FM[/last.fm.charts]

Chart styles are here:
Image charts for forums and blogs – Last.fm

There is also generator with short code which can be used in signatures.