As I write this, there are almost 3,000 projects in freshmeat's C category and almost 1,500 in the Perl category, but there are only about 400 projects in the Python category. SourceForge has similar statistics.
Comparing this with the current programming language statistics from Freshmeat, we compile the following table:
Language Growth (2001 - 2005) C 2.4 Perl 2.2 Python 4.5
The number of projects per programming language is consistent with Sourceforge's numbers:
Number of C projects /
number of Perl projectsC / Python Perl / Python Freshmeat 2.2 4.0 1.8 Sourceforge 2.5 3.8 1.5
(Consistency is caused partly by the overlap of projects in these sites.)
The article didn't provide numbers from Sourceforge, but noted that "SourceForge has similar statistics" so we can conclude that the growths are similar both in Freshmeat and Sourceforge. Thus, Python is catching up with at least C and Perl. (Though Python might be losing to other languages.)
Someone enthusiastic enough could gather more accurate statistics from Sourceforge's listings and generate nice plots of them. Scraping automatically all the needed pages from sf.net would be somewhat impolite, though, I think.