For the multiple file uploads you can put in the Other properties of the File Upload control
multiple="multiple"
This allows you to select multiple files. Nice. Domino handles this well, and means you can avoid having multiple file upload boxes.
The caption in chrome changes to "Choose Files" instead of "Choose File"
NB This works in firefox 3.6.3 as well.
The other lovely feature that Chrome allows is the drag and drop feature.
You can drag and drop the files from windows explorer over the "Choose Files" captioned button.
When you are over the Choose Files button the button highlights and then you can drop the file(s) into the browser.
Nice, much better than using windows explorer to find the file.