I tried to be a good Apex Community Citizen and put this in the Tips and Tricks Studio, but it hasn't been updated since HTMLDB 2.0 and I couldn't select Apex 3.0, so I'm putting it out here for now.<p>
I'm sure I'm not the first to figure this out, but I thought maybe it would help some newbies. Also, if someone can think of a more efficient way to do this (probably through AJAX), I'm all ears.<p>
1. Enter help text for your items (Page Items)
2. In the Utilities Page, go to Apex Views and query APEX Application Page Items to get the ITEM_ID of each Page Item with help text.
3. On page 0, create hidden items for each of the Page Items with help text. The source of these items will be SQL Query, and the query is: <p>
select ITEM_HELP_TEXT
from APEX_APPLICATION_PAGE_ITEMS
where APPLICATION_ID = <your app id> and PAGE_ID = <your page id> and ITEM_ID = <your Page Item id>
<p>
Be sure to set the Source to "Only when Item is null..." to prevent running the same query over and over when the page is rendered.<p>
4. Back on your page, set your pre-element text to "<span title="&P0_ITEM_HELP.">", using the appropriate item name from page 0, and set the post-element text to "</span>."
<p>
Now run the page and when your mouse hovers over the item, the Item Help Text will appear as a tooltip.