Hi Mark,
Many of the addins are repackaged macros written in VBA,
those written in C++ will be much faster. But I think more important
to you would probably be to ask for what you are looking for.,
besides free, of course. Don't include the word free in your search
you'll probably end up with hits for anything but free (particularly
in a web search as opposed to newsgroups).
Besides the sites already mentioned, several MVPs have addins
at Stephen Bullen's site
http://www.bmsltd.co.uk/MVP/Default.htm
look at his own page as well look for the word addin
http://www.bmsltd.co.uk/Excel/Default.htm
John Walkenbach has many scattered throughout his site, try his search
http://www.j-walk.com/ss/excel
Then you could search the web for
Excel and addin
which might keep you busy for years,
and search Google Groups in the Excel groups for addin
http://groups.google.com/advanced_group_search?q=group:*Excel*&num=100
But don't overlook macros, there are even more of them for
specific tasks.
If you get too many hits with addin group:Excel (8,700) you could throw in the word
MVP (2,260) but that's like asking who makes the best.ice.cream (3,010) and
limiting your selection to vanilla (424).
HTH,
David McRitchie, Microsoft MVP - Excel [site changed Nov. 2001]
My Excel Pages:
http://www.mvps.org/dmcritchie/excel/excel.htm
Search Page:
http://www.mvps.org/dmcritchie/excel/search.htm