This Win32 sendmail comes from the Tin archive at
ftp://ftp.wa.com/pub/users/ntnews/tin/utils 

To use it, place it in your path and put the following line in lynx.cfg.

SYSTEM_MAIL:sendmail -f me@my.host -h my.host -r my.smtp.mailer -m SMTP

You can use a specific path to sendmail if you want instead of putting
it in your path.

You need to change the three "my" values to reflect you local
configuration.  Also, it may not work if you have a different default
command interpreter than the Windows default.

Here are the instructions that came with it for people who may want to
use this for other purposes.

             Setting up sendmail.exe for use from within Tin
             ===============================================

Sendmail can use two transports, either MAPI or send mail over TCP/IP to a 
local SMTP server.  The following sections detail the entry required in 
your ~/tin/tinrc file.  Problems?  Send email to nigele@microsoft.com

Sendmail supports sending to multiple recipients.  The to list should be a
comma, space or semi-colon delimited list of recipients.

==

1) MAPI

If you want to edit using the MAPI dialog use: 

  default_mailer_format=sendmail -m XMAPI -t"%T" -f %U -s "%S" -F %F

Otherwise:

  default_mailer_format=sendmail -m MAPI -t"%T" -f %U -s "%S" -F %F

2) SMTP

  default_mailer_format=sendmail -f myname@microsoft.com -h myhostname 
                                 -r mysmtphost -m SMTP -t"%T" 
                                 -f %U -s "%S" -F %F