It is probably worth you spending a bit of time on the board researching – as the answers will already be on here, rather than us answer them all again:
I.E
http://www.partyvibe.com/forums/free-parties-teknivals/1253-definitive-guide-putting-party.html

http://www.partyvibe.com/forums/law/18482-temporary-event-notices.html

http://www.partyvibe.com/forums/law/3770-getting-illegal-parties-legalised.html

http://www.partyvibe.com/forums/free-parties-teknivals/48273-change-law-regarding-parties.html