Here below are some links to check out.

SWOP (U.S.): the sex workers organization of the United States (with lots of resources!)
NSWP: Global Network of Sex Work Projects
Behind the Red Light District: a blog about a window prostitute in Amsterdam
Transgender Christians: lots of resources about Christianity & transsexualism


Dutch (with English pages):

PIC Amsterdam: Prostitution Information Center
PROUD: The sex workers union of the Netherlands

Local health organizations (prostitution/sex work):

Netherlands, Amsterdam: P&G292 (practical & STI health)
Belgium: Cherut (christian)
Belgium, Antwerp: Ghapro

Netherlands, Rotterdam: FortaGroep (ask for Marijke Vonk)

Local health organizations ((mostly) human trafficking):

Netherlands: Fier! (including safe houses)
Netherlands: comensha (coordination)
Belgium, Antwerp: Payoke (including safe houses)

Note: The health organizations mentioned are organizations I recommend based on the information or experiences I have with these organizations. If you have concerns or would like to introduce me to a specific organization: I’d love to hear from you.