BERViewer

BERViewer is a Windows 95/NT program that allows the user to "view" BER/DER encoded files such as X.509 certificates and S/MIME messages. It is "shareware" and it only costs USD $10.00 to get the registered version. The unregistered version has a reminder dialog box that pops up roughly every minute. Below is a screen shot, showing two open files:

Click here to download a copy.