You can find you settings screen by pressing the options button during a match. Your invite code is at the bottom of that screen
It also dawned on me that you may want to know about contribution requirements. I am asking that you contribute $30,000 gold/wk, participate in at least 2 guild wars matches weekly, contribute 10 trophies, and meet the weekly individual seals goal. This is the minimum, If you want to do more it is welcome.
If your looking at this thread, your looking for a guild. Go ahead and give us a try!