Excel 2007 : Merging columns into email address

In terms of the concatenation

C1: =LOWER(A1&"."&B1&"@address.company.au")

where A1 holds First Name & B1 Last Name

If you wish for the above to be valid hyperlinks then

C1: =HYPERLINK(LOWER("mailto:"&A1&"."&B1&"@address.company.au"))

You can append the hyperlink string to alter the mail content, eg:

"mailto:etc...?subject=example&body=Hello%0A%0AHow%20Are%20You?"