uuencode is recognisable as email attachment in Ms Outlook, but in Outlook Express (at least in older versions) - is not.
This is shell script, but it may give you an idea how you can send attachments using uuencode:
cat file.bin | uuencode file.bin | mail someone@domain.com -s "file.bin"
uuencode mail attachments from other point of wiev are deprecated. However I use such technic for years now and it work well.