%wordpress I've created to tool to turn php functions into Wordpress widgets. I use the register_sidebar_widget function but it seems like wp_register_sidebar_widget would give me more options. Does anyone know if that is legal?
P.S. I also generate widgets in the new 2.8 format.
Legal? Sure. WordPress is GPL, you can do anything you like as long as you follow the requirements of the license.
register_sidebar_widget is deprecated--though it can still be used, but you could use wp_register_sidebar_widget. If you do use register_sidebar_widget might want to bracket it in an if ( function_exists('register_sidebar_widget') ) in case that function gets removed in subsequent versions.
Also, there is a plugin, Otto's PHP Code Widget, that allows PHP code in a widget.