Thanks to the new GMail AntiVirus Scanner, you cannot send or receive emails with exe, dll, ocx, com or bat attachments even if they are sent in a zipped (.zip, .tar, .tgz, .taz, .z, .gz) format (The .rar format is still allowed).
Since you cannot Turn Off GMail
AntiVirus Scanning, you can use these
GMail hacks to send program file
(exe), virus samples and other blocked
formats with GMail:
Use a free file hosing online service like Rapidshare, Megaupload or
Yousendit to upload your file and send
the link of the uploaded file in your
Rename the file: Change the file extension to fool the GMail scanner.
The new attachment could contain
instructions making it easier for the
recepient to derive the actuall
attachment type. For instance,
If you have lot of exe files to send, put them in a zip file and
change the extension of the zip file
as mentioned in the previous step.
Remember that GMail denies zip
attachments that contain exe files.
Pass-Protection won't work either
since GMail can examine exe filenames
even in password protected zipped
files as the archived filename
listings are not encrypted by the Zip
Use a different compression software like WinRAR which compresses
files in .rar format. GMail is
currently not scanning or blocking
.rar filetypes. But there is a high
probability that GMail might support
rar formats in future. In that case,
you can consider splitting the rar
files and attaching them separately
(like .r1, .r2..)
Important: I would recommend only the
first technique since all others
violate Google policies and Google
could even terminate your GMail
Source: Attach and Send Any File Type with GMail Like EXE, ZIP, Videos; Trick GMail Antivirus Scanner
On 05/14/2012 (today), I attempted to upload a .rar file that contained a .vb file - one of Googles banned file types. gmail does not allow .rar files containing banned file types anymore either.