> I am planning on selling software that uses a web
> capturing software as part of its functionality, but
> not its core functionality. I do not plan on
> releasing my application under the GPL. May I
> distribute HTTrack including its GPL and source with
> my non-GPL'ed application.

Well, this is possible, but only with restrictions. You have to ensure that
the following restrictions are fullfilled:

- distribute the unmodified version of httrack
- make sure that the original license is distributed among the program, and
put a clear statement that the standalone software and its sources are
protected by the GPL (and if possible, with the link to the original site:
<http://www.httrack.com/>) in the documentation and/or the program
- use httrack as a *standalone* application (that is, by launching httrack.exe
or winhttrack.exe through some execv() equivalent, or by letting the user
execute the program)
- do not link your program to any of the distributed DLL's (especially
libhttrack.dll) or executables
- do not use any part of the code or any related (docs, graphics, css,
documentation..) material in your application

(The big difference between GPL and LGPL is the library link part : you CAN
NOT link to a GPLe'd library)