The iPad's generally seen as a consumption device, but here are a few ideas on how to use it to help you focus on your work.
The Brooks Review discusses how moving distracting elements (such as Twitter) off your work computer and over to your iPad can help you regain focus while working. While the specifics may not apply to you directly, if you have an iPad you have the ability to shuttle over a number of services that may distract you throughout the day. For example, email and instant messaging are my two biggest interruptions and the iPad is equipped to handle them both. A quick search through the app store can help you find the things you'd like to abstract from your work and relegate to the iPad. From there you can set specific times during the day to move to your iPad and deal with your distractions or use the pomodoro technique with your breaks centring around the iPad.
An alternative method is the exact opposite of this idea. If you really need to focus on work and you can't rid your work computer of all distractions the iPad may be the perfect uni-tasking for certain tasks. Focusing on writing can often be a pain with everything else going on, but you'll find a large number of options for all types of writing. If you need an easy way to sync back to your machine, Simplenote and Evernote are both great options. For more information on setting up text capture and syncing, check out our post on The Holy Grail of Ubiquitous Plain Text Capture.