Resourcing Health and Education in the Sex Industry (RhED) is a state-wide health, education and support service for the sex industry in Australia. It's multitude of resources includes a magazine primarily written by and for sex workers.
They also include a helpful page aimed at university students interested in conducting research on sex work and sex workers.
QZap Queer Zine Archive, searchable with the tag "sex work"
Sex Worker Zine Project from South Africa, featuring the words and art of women and transgender sex workers
Stroll from Portland, OR, an education and outreach program by and for sex workers, which also produces the zine Working It