Got this fact while reading some blog..
Gmail upgraded the maximum attachment size from 10 MB to 20 MB. Gmail was quite forgiving and you could send more than 10 MB in some cases, but now it's possible to send at least 20 MB in one message.
Of course, few mail providers will accept a such a big message, so it's safe to send messages bigger than 10 MB to other Gmail accounts, to Yahoo Mail Plus or to other premium accounts.
It would be nice if Gmail showed a progress bar for the upload and if uploading files to Gmail was faster and more reliable. But maybe we're asking too much.
Cool, isn't it ?