Hi Sebastian,
we have different icons, texts, different output, like no location etc. - time(zone) on userprofile support (so when you have international attendees the webinar start-, stop-times etc. are matching there local time zones).
For the next release we are also going to add the ability to automatically inform the users with the webinar url x minutes before the webinar starts. Additionally you can offer them a link or even a flash file to download / view the whole webinar again after (You can already do this by editing the description and inserting content for participants only, but with the next version it will become even more easy).
Best regards,
Yves