How to apply as a middleman?

I was wondering if some one would lead me in the direction to apply as a middle man, or what I have to do.

Check that thread - http://forums.steamrep.com/threads/trusted-middleman-question.883/

To be honest, getting to a "middle man" of any sort requires time and investment in the Community.

Can I suggest that one path which can help build up trust and aid in the kind of interpersonal networking that can result in broadening reputation would be to try to become Admin of a good server/network. Quite often involvement in a community can lead to this kind of possibility.

It is very hard for "unknown" people to gain a foothold in real money transactions and there are many barriers to overcome, some real and some intrinsic, that often are a huge hurdle for newer players who aspire to such things.

its in the FAQ: http://forums.steamrep.com/threads/expanded-faq-recommended.7263/ bout halfway:

Q: What about rep on profiles?
A: Such rep is not recognized by SteamRep or most valid traders. Why? Any comment on a profile can be deleted by the owner of the account. Any negative rep can therefore be deleted. Also fake rep is too easy there for some checks cannot be done against them.

Q: Who or why should be repped?
A: Every community has their own rules on how reputation is handled, so please be sure to consult that particular community first. However, for more general rules on reputation, feel free to read DataStorm's Advice on Reputation.

Q: I want to be Trusted Seller.
A: http://www.sourceop.com/modules.php?name=Forums&file=viewtopic&t=111814
Its not an easy task to get. Be sure to read the reputation thread rules, for otherwise you may get your rep thread locked/deleted:
http://www.sourceop.com/modules.php?name=Forums&file=viewtopic&t=127233
http://www.sourceop.com/modules.php?name=Forums&file=viewtopic&t=115564
Remember: Quality is way more important then quantity. A 1000x 1 key reps are worth little.

Q: Ok, TS is too much, but how to gain rep?
A: Let traders rep you on your reputation thread(s) around in communities: this may be on SourceOP, UTC, or other communities where they admin rep threads.
Remember: Quality is way more important then quantity.

as for the Question to get to be a MM, there isn't a FAQ item for it yet. But in general, the people that gained a bunch of rep via their reputation thread get asked by peers to MM for them at times. That is all about their reputation between traders. I'll make a write-up of it later on for the FAQ.