Cntlm is an NTLM / NTLMv2 authenticating HTTP/1.1 proxy. It caches auth'd connections for reuse, offers TCP/IP tunneling (port forwarding) thru parent proxy and much much more. It's in C, very fast and resource-efficient. Go to http://cntlm.sf.net/
Download
cntlm - cntlm 0.35.1
Last Update: Nov 23 2007