In Outlook:

Method 1:  Go to Tools > Options > Preferences tab > E-mail Options and then select the "Read all standard mail in plain text" check box. You can also include messages signed with a digital signature, select the "Read all digitally signed mail in plain text" check box. Then go to Tools > Options > Preferences tab > E-mail Options > Tracking Options and then select the "Never send a response" radio box.

Method 2: The other option is to turn off the preview pane in Outlook.  Go to the "View" Menu > Reading pane > and select Off.  For messages you want to actually read you can then double click them.  Now only messages you actually double click on would you have to worry about privacy issues. This is less effective than method 1 above.

In Outlook Express:

Method 1: Go to Tools > Options > Receipts and check the “Never send a read receipt” checkbox.  Then go to Tools > Options > Read and check the “Read all messages in plain text” checkbox. This should protect you from anyone trying to track you automatically as long as you don't manually click on links in your email messages you are protacted.

Method 2: The other option is to turn off the preview pane in Outlook Express.  Go to the "View" Menu > Layout > and uncheck Show preview pane.  For messages you want to actually read you can then double click them.  Now only messages you actually double click on would you have to worry about privacy issues. This is less effective than method 1 above.