Hey, I want to make a proxy server,
what software should I use, which one uses the least resources?

Thanks

A proxy for what? http, ftp? If you want a solid http proxy that is very well developed, i suggest Squid. Depending on the traffic it can run on pretty low hardware requirements. We had a very successful Squid proxy running on a PII-233 with 384 in RAM. Squid ships with virtually every distribution and you can get it from squid-cache.org as well.

Ok so me and a few friends have cable connections and we have limited traffic (yes that sucks)
and I want to make a http , ftp proxy at a company in my city that has a fiber optic connection, and I want only certan IPs to be able to use it.

Can someone please guide me on how ot configure it?

Thanks

you then definitly go for "squid", however im sorry i can't guide from here howto configure it. Its pretty simple to configure a transparent proxy/cache server using squid.
Just google for it and then see you will find lot of howtos about squid.
also do point your browser to squid home www.squid-cache.org to download the squid.
I myself prefer the source installation of squid. I duno about you if you prefer binary package then squid rpms are also avaible or already have it with your favorite distro.
Last but not the least if you got any problem while running and configuring squid for the first time then join freenode #squid IRC server, there you will find nice ppl to help you out of your problems

regards

Or simply post here, as we have tons of squid gurus here. Squid doesn't handle ftp worth a damn, so you may need either frox or a routing table for ftp if you need it. Access control in squid is easy. If you are really new at this, I suggest using webmin to configure squid, it makes setting up a proxy pretty easy unless you have strange requirements.