Digital Signatures, adobe

Hey all,

I want to secure my pdf files when sending via emails. I plan on using digital signatures, but i just know theory stuff bout digital signatures. I dont know how to go about applying it to pdf files and getting my co-workers to receive and decrypt it.
I plan to use Microsoft certificates as well.

1. how to apply digital signatures to my pdf files (I'm using adobe standard 6.0)?
2. how do i get my targets to decrypt them?