As a formula:
=a1&char(10)&"This is the second line"&char(10)&text(b1,"$#,##0.00")
(and format the cell for wraptext--or you'll see a little box for that
char(10).)
As input, you hit alt-enter to force a new line within the cell.
in code:
dim myStr as string
mystr = "Something" & vbnewline & "something else" & vblf & "a third thing"
vbnewline will work for both Mac's and PC's.
vbLf is enough for PC's.