This is a simple module that converts a positive integer to its English equivalent (e.g. 20 => twenty). It has support for American and European conventions for the meaning of "billion" and up. The interface consists of a single exported subroutine. I use it for spelling out numbers in checks.
The author is unresponsive as of the time of this review. If anyone is interested in an extension to this module that has support for zero, negative numbers and limited support for decimal numbers, email me at CDOLAN @ cpan.org.
Update: I just learned about Lingua::EN::Number which has similar functionality, but appears to be much better written and supported.