I've tried both using export http_proxy=http://[username]:[pwd]@[proxy] and git config --global http.proxy http://[username]:[pwd]@[proxy].

I couldn't make it work. It looks like git uses Basic authentication:

Initialized empty Git repository in /home/.../.git/
* Couldn't find host github.com in the .netrc file, using defaults
* About to connect() to github.com port 8080 (#0)
*   Trying 10.... * Connected to github.com (10....) port 8080 (#0)
* Proxy auth using Basic with user '...'
> GET http://github.com/sunlightlabs/fiftystates.git/info/refs HTTP/1.1
Proxy-Authorization: Basic MD...
User-Agent: git/1.6.1.2
Host: github.com
Pragma: no-cache
Accept: */*
Proxy-Connection: Keep-Alive

< HTTP/1.1 407 Proxy Authentication Required ( The ISA Server requires authorization to fulfill the request. Access to t
he Web Proxy filter is denied.  )
< Via: 1.1 ...
< Proxy-Authenticate: Negotiate
< Proxy-Authenticate: Kerberos
< Proxy-Authenticate: NTLM
< Connection: Keep-Alive
< Proxy-Connection: Keep-Alive
< Pragma: no-cache
< Cache-Control: no-cache
< Content-Type: text/html
< Content-Length: 4118
* The requested URL returned error: 407
* Closing connection #0
fatal: http://github.com/sunlightlabs/fiftystates.git/info/refs download error - The requested URL returned error: 407

Google search returned mixed and probably not updated results. Somewhere it says that curl is (was?) used under the hood, but its options are (were?) hardwired into code. For example,

curl --proxy-ntlm --proxy ...:8080 google.com

works, and I'd like to use the same option with git.

I need some more definite answers here: has anybody succeed using git through Windows proxies? Which version?

Thanks.