Similar services that you mention are performed commercially. A popular model is that photographers would send all or a culled selection of images to the company and they will further cull and perform basic editing on the remainder.

Charging Method

Charging is rarely done by the hour since speed is greatly dependent on skill level and a customer shouldn't be charged more simply because the editor is less efficient. Instead, industry standard is charging based on the number of images the editor "touches" and the level of services provided.

If you want the editor to cull through your full event, they are essentially touching every image as they decide whether to keep it or not.

Basic Editing

Basic editing (exposure, color correction, cropping, etc) ranges anywhere from $0.10 to $0.50 per image. If you've already culled your images and are requesting basic editing on all images you send, you are often charged more per image than if you send in all images from an event and have the editor cull. This is because an editor is deleting roughly half of your images without editing and still charging you per image.

Check out some commercial editing comapnies to get a feel for the industry standard. Some quick searching brought me to roughly $0.15 per image for basic editing. You can use this for reference: http://www.proimageeditors.com/postproduction.htm For a service that breaks down the costs by task (including categorizing), this is a great reference: http://www.vitaledit.com/Services.aspx

Advanced Editing

Advanced editing can be upwards of $2.00-$5.00 per image depending on the level of advanced editing provided. This can be everything from removing an object from the image to "airbrushing" portraits.

Sorting / Renaming / Collections

The task of sorting into collections is something that can be easily automated. Personally, as long as there is metadata of the date the image was taken, this process is only a few minutes worth of work and wouldn't warrant a significant up-charge in addition to what's mentioned above. The example I found was $0.03 per image.