The articles listed below contain VBA code samples. Additional code samples are listed at Developer Samples

Create a List of Meeting Attendees and Responses
How to get a list of Outlook Meeting attendees and their responses using VBA. This code sample gets the appointment details and attendees (along with their responses) and inserts it into a new Outlook message form, which you can print, send or copy the data fir use in other applications.
Developer Tools
This is a collection of tools used to view inside MAPI message stores, including Exchange mailboxes and PSTs. Two of the tools, MFCMapi and MDBVu32 are provided by Microsoft. While these tools are designed for developers, they can be used by anyone with basic knowledge to browse for and delete hidden items in a mailbox

Bulk Change Email Display Name Format
Use a macro to make changes to any Outlook contact field, by folder or by selection.

Edit and Save Outlook's Read-Only Attachments
Solutions available! When attachments are opened from a message in Outlook 2010, they are read-only. Users cannot edit the attachment and save the changes back to the message, they need to save the attachment to the hard drive and reattach it.

Warn Before Sending: Checking Contact Categories
Warn before sending mail macro: Check recipients contacts for specific categories before sending.

Remove Cancelled Meeting Requests from Resource Calendar
How to remove cancelled meetings from an Exchange server resource calendar.
Map Contact Addresses or Meeting Locations
How to create a map or driving directions to one or more Outlook Contact's address or Meeting locations using VBA.

Save email message as text file
Use an Outlook macro to save the selected message as a text file, or save the selected messages in a single text file.

How to Process Mail After Business Hours
I have a macro that defers sending messages that are composed during a specific time period, such as during the overnight hours. After several users asked how to send responses or forward messages if the new messages arrived during the overnight hours, it's time to add macros for incoming messages as well. I would like
Use RegEx to extract text from an Outlook email message
Getting text out of a message body isn't as hard as it sounds, provided there is something in the body to search on. For example, if you are looking for a tracking code in an email and it's always identified as "Tracking code:" , you can use VB functions or RegEx to get the string.

Create a Series of Tasks using VBA
Using VBA, you can automatically create a series of Outlook tasks based on a task or appointment. You can create the tasks leading up to an appointment or task or following an appointment or task.

Search Calendars for Appointments
A user had a number of calendars, both in his own mailboxes plus a handful of shared calendars. While Outlook can search all of the calendars, he wanted an easy way to restrict the searches to specific calendars and also see which calendar the appointment was on. The solution: a macro. We used the macro

Merge or Split Conversations
A major complaint about Outlook's conversation view is the inability to split and merge conversations. While Outlook doesn't offer the capability, you can use a macro to merge or split conversations.

Update Folder Permissions using VBA
How to assign, change, or remove folder permissions in an Exchange mailbox using Outlook VBA and Redemption.

Automatically create a task when sending a message
How to automatically create tasks for message you send using a VBA macro.