Does anyone know of any good plugin, preferably easy to install and configure, that you can use to hide any affiliate links you choose to use?
Why don't you use one of your domains? No plugin, no tinyurl or whatever. You create your own sub domains and you redirect them to your affiliate URLs And you can use those sub domains everywhere (newsletters, ads, forums signatures, WP blogs...)
Why not just use a php redirect? You can set up your links to be whatever you want and control the link url in the redirect code.
The simple way is to use HIDEPOST plugin and use TinyURL. I use that for some of my sites. It works great. You can also use WP AFFILIATE. Goodluck..