..or with the "use" syntax, simply include the local version of the module (that you have copied in as a support file).

This tactic does NOT always work however - many perl modules do use C and other compiled portions - these types of modules, of course, will not function by just being copied in, in most cases.  However, in Mail::Sendmail, as documented by the author in it's POD, "Only requires Perl 5 and a network connection." - and is a suggested method in PerlDoc's Portable Code page.

- so fly free, and enjoy the easy use as a local module.

Update:
This might help as well - look towards the bottom for the part on "what if i do not have permission to install..." - thanks footpad!