|Can we use ruby for commercial
 |application?

 Yes.

 |Do we need to distribte our application with sources?

 No.  If you're using regex.c comes with 1.8.2, you have to allow
 re-linking the binary (via supplying object files or dynamic linking),
 because it's LGPL.  If you are using Oniguruma new regex engine, you
 have no such restriction.

 Gabriele Renzi added:
  IIRC 1.9 in the cvs already has oniguruma as the standard regex lib.