Less amazed to find out that the current #1 (On the chart for the last 227 weeks!) was the 'Mission impossible theme'.
The current list is avaialable
at Billboard.com - apparently derived from Nielson data, that Neilson, in turn, collects from the celphone providers.
No statement as to methodology for the data, per my usual experience from Neilson. It'd be interesting to see a full report from their 'RingScan' service to see what all they're tracking. Hmmm.