switch2mac

With WP-SOS-Donate you can simply add a sidebar widget for help donation e.g for haiti. 
After the plugin is activated, you can drag and drop WP-SOS-Donate Widget to your Sidebar. 
You can choose your own headline, the color of the subline, the charity link and the picture in the widget. 
If this is not enough for your site, you can define your own template.

WP-SOS-Donate Donation Sidebar Plugin

With WP-SOS-Donate you can simply add a sidebar widget for help donation e.g for haiti

Kreezxil

Places a black ribbon in the upper right corner of your blog displaying the word “Donate” in white text. You can set the link to any URL you choose via the settings page. Now with vertical offset options. You may also set the link title hover message. By default it is set to the Redcross donation page.

Donate Ribbon

Places a black "Donate" ribbon in the upper right corner of your blog with the option to set the Link and Link Title.

WP-SOS-Donate Donation Sidebar Plugin vs Donate Ribbon