This Applescript will read the current Excel Worksheet (with the URL in Col A and the name of PDF in Col B) and d/l to the Desktop.
tell application "Microsoft Excel"
tell active sheet
tell used range
set rc to count of rows
end tell
set theList to get value of range ("A1:B" & rc) as list
repeat with theItem in theList
do shell script "curl " & item 1 of theItem & " -o $HOME/Desktop/" & item 2 of theItem
end repeat
end tell
end tell
This does not handle username and password authentication, but can easily be added to the curl command.
Take a look at: man curl There's options to deal with passwords. Googling curl password can also give some help on dealing with passwords (see; http://stackoverflow.com/questions/2594880/using-curl-with-a-username-and-passwo rd) (but you need to be careful in sending passwords in the clear).
So, changing:
do shell script "curl " & item 1 of theItem & " -o $HOME/Desktop/" & item 2 of theItem
to:
do shell script "curl -u username:password " & item 1 of theItem & " -o $HOME/Desktop/" & item 2 of theItem
(but see warnings re: username and password in man curl)