Large mail attachments and choke

I have tried to email rather large attachments using on several ocassions. I have a highspeed connection and so do the recipients - wouldn't do that to a dialup buddy!

It always dies. message never sent. In addition this then places the entire message (w/ attachment) in my sent mail directory.

This causes a freeze whenever I click on my sent mail icon (it's trying to index the messages acording to the status reporter). I've had to delete the entire sent mail mailbox (losing some important stuff unfortunately - had a backup of some of it but not that day's work) - mail creates a new one next time you send a message.

Is there some limit on mail sizes? This would be ridiculous if true. Also, have tried sending the messages using 4 different mail accounts just in case has some limit on size. I know the other 3 do NOT. Same result.

Any ideas?