New To GIT have some (probably simple) newbie questions

[Ryan Bilesky <rbilesky@gmail.com>]

Sorry if these questions seem simple but I am new to GIT, I've done
some searching about how it works but I still have some questions that
I hope someone on this list would be kind enough to answer.  I am
using msysgit on Windows 7.

For some of my projects I have to comit changes to SVN.  So I did some
research and found out how to use git-svn so I start by right clicking
on the directory I want to store my repository in, and I select Git
Bash Here.  I enter in the comand

git-svn clone -s --username=myusername https://mysvnrepo/svn git

and that works and it creates a local git repository that is cloned
from the svn repo, then if I

git-svn dcommit

that keeps then synced up, but there is my first issue, manually
syncing, so I look at git hooks, so if I create a file called
post-commit in the hooks directory of my local git repo with the
following content

#!/bin/sh
git-svn dcommit

that should work to automatically sync my local git repo and the
remote svn repo upon me committing to git right?

What I have no clue how to do though it to get this to work with
another git repo, I mean I can use the gui to clone a git repo, but
how do I sync them up.  The reason being is I use a git hosting
service where I want to mirror all my commit to, just as a backup
mostly.

How can I sync up my local git repo with the remote hosted repo AND
where necessary svn using svn-git?

My final question is a matter of work flow.  I have a local it repos
on my machine using msysgit, as well as hosted git repos with an
online service.  Since I am a single developer its easy to just sync
my commits back to the remote repo for each project I have.  But if I
do get another developer or two to help me how does that work, do we
all just sync to the one hosted repo or should we all sync with
another too?  And if so how do I sync with multiple git repos.

Thanks in advance for your help.