I recently found this ?, and started updating the control to work. Then, I came across the right way to get rich text in a form in MSO 2007+:
Insert or add a rich text field
It says you need to have a memo field in a table, and set its text format to Rich Text. Since the solution is a bit opaque, I'll continue with what worked for me: I then go into form design, and create a text field. I set its data source to the table's rich text memo field; and its "Text Format" property to "Rich Text". I set its "Scroll Bars" property to "Vertical".
Now, I get some nice text formatting options in Access 2010; but it's kinda stupid the way they've implemented them. There's no format painter. Also, if I want to e.g. set the font to Times New Roman to pitch 11, it doesn't let me; but makes turns it into 10; although I can select 12 also - but not 11. If, however, in Design View, I set it the field's font to "Times New Roman", and set the font size THERE to 11, the font is size 11 by default. I can paste things into it in 11 pitch, by first pasting them into Notepad, to strip them of their formatting attributes, and then from Notepad into my field, to get pitch 11 text; or I can paste pitch 11 from elsewhere.
This has the advantage of getting some handy text formatting controls to light up on your home ribbon, and lets you format stuff more or less properly.