Company Logo

For the company logo, I have opted to use the services of 99Designs.com. This service is a "crowd-sourced" logo design one where 10,000 of designers from all over the world can be reached. 

How it works

Designers submit designs, you rate them and upon contest expiry, you choose a winner.
The overall experience was overly positive: great customer support, great value for the price:

• ~100 designers submitted
• ~200 designs
• Total cost: 580$US
• Total time to result: ~14days (extended period to pick a winner available)

Overhead
The one notable downside was the amount of overhead required to manage a successful campaign.  I received upwards of 100 email comments but most of them I could deal with just by "rating" the associated design submission.

Be prepared though to dedicate an amount of attention proportional to the prize contest amount i.e. the higher prize you offer, the more submissions/comments you will receive.

Drawback
The first contest one runs cannot be a "blind" one i.e. everything thing is public. "Blind contests" are only available the next time around.  The drawback of this approach is that the more you comment on your preferences, the more copy-cats you will get tagging along.