Davey Shafik has a new posting over on his blog (Pixelated Dreams) about a new package he worked up for PEAR called PHP_CompatInfo (v. 1.0.0-stable)

PHP_CompatInfo will parse a file/folder/script/array to find out the minimum version and extensions required for it to run. Features advanced debug output which shows which functions require which version and CLI output script

With this handy little script you can quickly and easily configure a web server instance tailor made to what that script might need to run.

For more information on this package or to download it, check out its PEAR information page...