I am presenting Git to a 10 man programming team who currently use Visual Source Safe.
They need to host their Git server inside the company. Windows or Linux. Direc
That's pretty much the technique I use. It's a hassle to set up accounts and keys for everyone, but that only needs to be done once.
As a bonus if you lay things out right you can have a read-only repository available at git://whatever or http://whatever and your writable repository at git+ssh://whatever.
EDIT: gitosis does look pretty neat, although you might want to have individual accounts for all your developers at some stage anywhere.