Several options.
If you are looking to only do this for a short time in meetings, you can set your sound profile to "silent" and receive no notifications at all.
If you still need to hear the phone ring, set it to "Phone only".
If you are looking to get rid of the notification altogether, Open your "messages" folder, press the BB key, and open "Message Alerts". You can then set the notification to whatever you want, be it a tone, nothing, or vibrate only.
Sounds folder > phone calls only/other preference. For custom contacts 2 be included in filter, set contact alerts > w/in each, msgs > email/other > active profile.
I create a "custom profile" for when I'm at work. I have email messages set to vibrate only, but still have audible alerts for SMS and voice calls. (Because I don't need my BB telling me I have a new email when I'm sitting at my desk with my email open, and I don't want it going off during meetings). If you don't want to silence EVERYTHING, nor do you want to have to adjust your email setting every time you have a meeting, I would suggest creating a custom profile.
Just go to Sounds and select, "custom profiles --> add custom profile" By default, everything will have the "normal" setting, so you only have to customize the items you want to differ from your normal profile, such as email alerts.
Note:
Unlike preloaded profiles in sounds list, custom profiles override all custom contacts settings (obviating necessity of active profile selection).
