unsalkorkmazok.. i am using Codestyling Localization to edit .po files. this plugin just rocks!
tip is if you move your bp-themes from wp-content/plugins/buddypress/bp-themes to wp-content/bp-themes you can't see lots of translate in po file.. so dont move it.. just copy it. when you keep your templates copy in wp-content/plugins/buddypress/bp-themes you can translate them from this plugin easily.
http://wordpress.org/extend/plugins/codestyling-localization/
