Please help

I am trying to automate a spreadsheet and have come across
the following problems:

1. I want to enter dates and times in one column,
whenever the corresponding entry is altered in another
column. How do I do this Visual Basic?

2. I want to convert data, on entry, in particular cells
from lower case to upper case. I can use validation rules
to force upper case data entry, but this is not the
complete user-friendly solution. How can I 'format' the
cells so that any data entries are automatically converted
to upper case?

3. And finally, I wish to trap the 'Cancel' and 'No'
button returns from the SaveAs dialog box. The SaveAs
command does not appear to return a response code in the
same waythat the GetSaveAsFilename command does. How do I
get round this.

Many thanks for any light you can shed on these problems.