I avoid the provided CVS because I don't really want experimental, broken, and testing code out there.
Upload at
ftp://upload.sourceforge.net/incoming and go to the File Releases page under Admin on your project page. Normally you will have a package for each portion of your project (i.e. Binary, Library, Documentation, etc.) and will create a new release in each package for the version. As an example:
Package: Binary
Release: program-0.1
program-0.1-src.tar.bz2
program-0.1-i386.rpm
Release: program-alpha
program-alpha-src.tar.bz2
Package: Documentation
Release: program-0.1
program-0.1-doc.tar.bz2
ta0kira