mohanjith

Code Master

Helps you make the site available via https and http with no effort. Just install and activate 
and say good bye to SSL errors without forcing users to access via http or https only.
<h3>Notes & Credits</h3>
This plugin is written by <a href="http://mohanjith.com/" rel="nofollow ugc">S H Mohanjith</a>.
You should follow us on Twitter <a href="http://twitter.com/codemasteroy" rel="nofollow ugc">here</a>.

WordPress SSL

Have been using this plugin to resolve SSL errors for quite a while.  Has not failed and works just as advertised.  Ensures all links to resources are on the correct protocol.

Has worked well for a long period

Seamlessly map URLs to SSL if the site is accessed via SSL.

ldirenro26

No need to swap all links in your site to https. Just install this plugin, active and your site will be migrated automatically. Tiny but flexible plugin, that helps to migrate your site from unsecured to secured version (from http to https). We are planning to support this plugin.

Force SSL Switcher

Tiny but flexible plugin, that helps to migrate your site from unsecured to secured version (from http to https)

WordPress SSL vs Force SSL Switcher