try http://office.microsoft.com/en-us/templates/default.aspx

download and use the ready made templates..

the authorized signature all that you can add it yourself.. just open MS Word and customize.

yes, you can send it by post but of course, meeting up with the person allows you to have a friendly conversation before 'demanding' money. but if the person is very far away, i suppose mail is fine.

if you included an extra envelope and stamp, that's added convenience and appreciation. it might also help you get your payment faster because you're helping them out with a step and all they have to do it post the item.

however, if i were you i'd be hammering my friend since he just left the company without informing you of his resignation and who you should be in contact with when he's gone.

the danger here right now is the passing on of responsibility in that company. the person says contact that person and the next thing you might find is that they'll say check with superior and whatever nonsense.

that's why nowadays most companies or freelancers have demanded a minimum 50% payment before the start of project.

hope that helps and you get your payment.

I downloaded awhile ago.

Did you guys know, 37Signals also has opened their recent book online for free. Can't download a PDF version though.

Anyway, yeah airgid's book is quite a nice read.