Four Newsgroups you may be interested in are:
soc.feminism is a moderated Usenet group with a lot of good information and discussion.
alt.feminism was created in 1992, by people who do not want to use a moderated group.
soc.women is not specifically feminist, but is worth mentioning.
talk.abortion is the place to go if you want to discuss abortion issues.
There are others that may interest you so it is best to do a search using some key words such as women etc. If you can't find a newgroup that suits you it may not be there. You may even like to think up one to start yourself.