Here are a few links you should bookmark and follow:
Props - Eric Hart
A fantastic resource from blogger Eric Hart who not only enjoys discussing props and the building of them but also makes a living doing so. Also includes great links to many who are in the actual business of making props for stage and more. Check it out.
I am a horror geek at heart and as such I am a fan of HP Lovecraft. Propnomicon takes that love and goes a step beyond by taking the time and dedication to make props based or inspired by the Lovecraft mythos. There are tons of prop making goodies to be found there including aging paper tutorials and some paper prop downloads. A fantastic site that is worth the visit.
Very much similar to Propnomicon. The site also includes great tutorials on props and has it's own collection of paper props to download. A brilliant site and also well worth a visit.
THE PROP BLOG
Here is another fantastic blog dedicated mostly to cosplay which includes tutorials on making fake weaponary and costumes that are beyond imagination. It is also a great resource for anyone in need of purchasing sheets of Styrene. Check it out.