There are two things to consider:

The directory layout for SVN usually looks like this:

/trunk/     # <- development usually happens here
/branches/  # <- for storing branches
/tags/      # <- for storing tags
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Inside the /trunk/ directory you usually put the layout for a module. There's a standard layout that most CPAN modules use. It looks along these lines (where most are optional):

lib/        # .pm files
t/          # unit tests
bin/        # scripts
extras/     # whatever..
examples/
doc/
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Take a look at Module::Starter which might be helpful for you.