http://rpf.prop-planet.com/ very active forum for discussing primarily replica props. Forum has a more heavy handed approach to moderation.

http://mp2c.com/forum/

http://www.replicaprops.com/forum/ forum for discussing replica props.

http://mpdf.ipbhost.com/ forum for discussing screen used props and costumes only.

http://p075.ezboard.com/breelprops forum for discussing screen used props and costumes.

http://p067.ezboard.com/bmatsucorp

http://1.myfreebulletinboard.com/?mforum=wwwlordoftherin

http://p220.ezboard.com/bculttvman scifi modeling message board from Culttv.com

http://www.angelfire.com/mi/JohnnyrumsRecPages/icons.htmlpage
archived icons related info and message board

Costuming Forums

http://thedentedhelmet.com/forums/ forum for Star Wars costumers

http://www.501st.com/messageboards.htm message board for the 501st a Star Wars Dark Side costuming group.