There is no Help entry for the new typewriter tool in Acrobat 7.0.5
You can get a tech doc from Adobe's web page
Using the Typewriter Tool (Acrobat Professional 7.0.5 on Windows and Mac OS)
You need the updates for Professional (and Reader for some clients)
Adobe Acrobat 7.0.5 Professional Update- English, French, German and Japanese
Adobe Reader 7.0.5 update - English, French, German and Japanese
To use the new tool, choose the new menu item under Tools
There are four options (decrease/increase text size/line spacing), and type away for those "forms" that have no fields.
You can also enable the document for Adobe Reader, make sure you understand the limitation.