Most of the users do not know that in Microsoft Outlook the storage limit for a single user's .PST file (the file used as Outlook's message database) is 2 GB. If a .PST file exceeds to over 2 GB, it can become damaged and some mail items may be lost.

Cached Exchange Mode is a new great feature in Microsoft Office Outlook 2003. Cached Exchange Mode permits Outlook 2003 to use a local copy of a user's mailbox while Outlook 2003 maintains an online connection to a remote copy of the user's mailbox in Microsoft Exchange 2003.  

Here is an update from Microsoft for Outlook 2003's junk email filter. This update enhances the junk e-mail filter, helping to provide a higher level of protection against junk e-mail.

Download the update from Microsoft

For more, read the KB Article 

Situation:
When you try to book a resource like a conference room, for example, by using a resource mailbox that has been configured to automatically accept meeting requests, the meeting request is not automatically accepted. Additionally, you cannot book the resource, and you do not receive the following confirmation message:

• On the Tools menu, click Address Book.
• Click the New Entry button.
• In the New Entry dialog box, click New Contact.
• In the Put these entries drop-down list, click the address book to which you want to add the contact, and then click OK.

Introduction:
Under Outlook's default settings, deleted item recovery is possible only from the deleted items folder.  The following registry modification will allow one to recover items from any Outlook folder, including items that were hard deleted, using shift-delete.  It should be noted that the prerequisite for recovery of any deleted items, is that a deleted items retention time has been specified for the private and/or public information store on the Exchange server.  Only items deleted within the specified retention period are recoverable.  The following solution has been tested, and is known to work on Microsoft Outlook 97,98,2000, and 2002 (XP).

You are able to add members to your distribution list in two ways. The first way is adding people from the Global Address List (GAL) in Outlook, and the second is adding people from your Personal Contacts. Follow these steps to create a personal distribution list.

These procedures are for modifying a distribution list that you have been made the owner. These DLs are stored in the Global Address List.

This tip involves adding an icon (really a .vcf file) to the end of an email that when the recipient double clicks it, will create a new contact with all of the contact fields automatically filled in. The recipient then only has to select save and close to add this contact into to their address book.

There are two locations for distribution lists (DLs). Once is the Global Address List (GAL), and the other is your personal contacts. There is no way to print the membership of a DL that is part of the GAL. However, you can print your own DLs that reside in your Contacts.