Before installing gpg4win-2.0.1.exe the gpg4win webpage advises the use of an integrity check using the sha1sum program. However, sha1sum seems to be exclusively for linux so how can I check the integrity of the download gpg4win-2.0.1.exe on a Windows platform ? Thanks.
read this [http://www.gnupg.org/download/integrity_check.html] to use GPG in verifying your download, then download this [http://ftp.gpg4win.org/gpg4win-2.0.1.exe.sig], the signature file of that particular version of gpg4win.
To add on a Windows platform you might also look at HashTab or HashCalc as alternatives.
http://beeblebrox.org/hashtab/
http://www.slavasoft.com/hashcalc/
Personally I use HashTab on my Windows 7 laptop.