TouchDown

Is there a way when you flag an email in Touchdown that it be synced to Outlook so that the email is also flagged there & vice versa?

Yes, for this you long-press the email on the TouchDown email list and select the option to flag the email. This may not work on some servers though, so it matters which version of exchange is being used (i think it is known to work on exchange 2007 onwards).

-g