Now I’m working on Drupal I need to keep track of my work - and merge in the changes from ‘upstream’.

here’s the useful info I found …

Drupal advise
Drupal.org » Forum » Support » Post installation : Repository setup
http://drupal.org/node/118936

Vendor Branches
http://svnbook.red-bean.com/en/1.0/ch07s04.html

Subversion Externals
http://svnbook.red-bean.com/en/1.0/ch07s03.html

svn load dirs (need for upgrading the vendor release)
http://docs.ofbiz.org/display/OFBIZ/SVN+Tips+-+svn_load_dirs+Vendor+Branch

CVS to subversion scripts
http://drupal.org/node/71232

Update Status (to track new modules)
http://drupal.org/project/update_status

In the end I’ve decided to put all my projects in one repository
(I’ll need to upgrade trac 0.11 soon to host project management on a
per project basis)

Each project has a copy of drupal core + contrib modules I plan to use svn:externals to link in my own modules