The AutoCorrect feature in Microsoft Office 2003 is a handy feature, replacing common spelling errors for you as you happily peck away at the keyboard.  It can also be used to speed up the typing of common, complicated, or lengthy terms.  Essentially, you can use it to create macros that will be replaced with longer, more cumbersome phrases automatically (and without errors). 

For example, you could create an autocorrect for the letters 'hspb', setting it to correct to 'heat sealed plastic bag'.  If you have to type this several times a day, it's easy to see the speed benefit. 

That same set of autocorrect macros is shared by the whole Office suite.  So, if you create autocorrect entries for yourself in Word, they'll be available in Excel, Access, Infopath, etc. 

A coworker of mine recently wondered why her just-added autocorrect entries weren't working in Infopath forms.  They worked great in Word, but Infopath just ignored them. 

The solution I found is that any autocorrect entries stored (in Word) as 'formatted text' will not work in Infopath.  Entries stored as 'plain text' work great.  So, even though Word will turn two-hyphens-and-a-greater-than (-->) into a pretty arrow, if you store that in an autocorrect, Infopath will ignore the whole entry.  Here are a couple screenshots of what I mean:

Formatted text entry

Plain text entry

For this example, I stored an autocorrect entry (shop) that will replace with 'shopping bag'.  I stored 'shopping bag' as formatted text and tested it in Infopath...only to find out it won't work.  Changing the entry (in Word's autocorrect list) to plain text ('shop1' for this example) makes the entry work in Infopath as well. 

Notes:

• It looks like you can tell the 'formatted text' entries in the autocorrect list by the asterisk (*) at the end of their text (aside from selecting each one and noting the 'Formatted text' radio button is selected). 
• Access the autocorrect feature by clicking Tools>Autocorrect Options in Microsoft Word.