Internationalisation was added in the H.323 and ILS parts of GnomeMeeting. You can check a GnomeMeeting session in Bulgarian here (thanks to Slavka for her patience during the tests and to Robert from Equivalence for his help):

- GnomeMeeting Bulgarian session

Netmeeting doesn't support this of course, but the feature will be available in the future 0.95.0 release of GnomeMeeting (together with an improved Quicknet card support and a better druid helping to configure the devices).
If you plan to compile the nightly snapshots, please use the OpenH323 CVS. Instructions are available here.