@Chris,

I recommend making sure you've got the warehouse app/module installed and then making sure you've got technical features ticked in your user settings:

Settings >> Users >> [Your username here - eg. Administrator] > Tick 'Technical Features'

you'll then need to refresh your browser.

Once you've done this go to:

Settings >> Sales >> Default Options >> [Tick 'Allow adding shipping costs'] > and then Save

and then:
Warehouse >> Delivery >> Delivery Pricelist >> Create >> Add an Item [in the 'Grid Definition' area]

To add these charges to a quotation for example go to:

Sales >> Quotations >> [Create New Quotation] >> Delivery Method

I think this should be what you're looking for as it is an implementation of table rates, or matrix rates. Alternatively there are a number of shipping connectors that have been built in the community so far that connect to UPS, FedEx, etc. via their respective API's.