Why doesn't plugin foo work in applyplugin?
Applyplugin doesn't obey the LADSPA_RANGE hints (It's not reqired to). Several of my plugins are amplitude dependent and thye guess that the nominal 0dB of the system is +-1.0f (refer to arguments on the linux-audio-developers mailing list if you're confused). This is true for nearly every system except applyplugin.
Workaround: add "amp_1181.so amp -89" before the plugin you want to use adn "amp_1181.so amp +89" after, or, install ecasound - it has actual features too ;)
Update: the pre-release of the LADSPA 1.1 SDK fixes this problem, you should get a copy of that if you want to use applyplugin.
What licence are they available under?
Are they available for systems other than LADSPA?
Not that I know of, but there are LADSPA wrappers for pd, and possibly other systems.
What plugins have you written
Here is a list of the plugins that I have working to date.
Listed next to them is the amount of CPU power they take when running, and the number of PIII cycles they use per sample. Those aren't particularly wonderful CPU usage measurments, but its really hard to get anything accurate and meaningful. Expect it to vary from machine to machine a lot anyway.
How to contact me
If you want to contact me about these plugins, you can mail firstname.lastname@example.org.