Wow!
This is exactly what I had to last week. Fingers crossed at the moment, the deadline is Wednesday for applications. We have five to go around so......
Here is the text of what I wrote for the Head. Obviously it is personal to me, but perhaps it would be of some help to you. (edited to remove personal references!

)
Date: 1-9-02
Subject: Laptops
From: Dr
To: Sd
I would like to bid for one of the five laptops available to staff on the following grounds:
• There is already a digital projector in F7 that I use extensively for my teaching. The provision of a laptop to link to this, rather than the rebuilt desktop used at present, would enhance the performance of this expensive piece of ICT equipment.
• I keep my registers of attendance and marking on PC, and at present this is on the network. A laptop with network access from my desk would enable me to manage these better and transfer data between home and school with ease.
• There is no screen for the PC in my room except the digital projector, and a laptop would make it easier to use the set up in my lessons.
• As part of one of my department's GTP she needs to develop ICT skills. I would be able to create lessons with her on the laptop using PowerPoint etc and then she could use them in F1 with the portable digital projector that is available for staff.
• The GTP teacher would also be able to take the laptop home with her when necessary to work on ICT work, and I would be able to offer phone support in the evenings to facilitate the best use of this.
• As part of the ongoing program that the History department has to develop the intranet in school, I would be able to keep the large and extensive files that make up the intranet on the hard drive on the laptop as well as the network to enable me to work on them at home.
• I write PowerPoint presentations on my home PC that are often up to 10-20Mb in size including video and music. To be able to connect the laptop to my PC using a LAN connection and have instant transfer of data would improve the efficiency of my work for school.
• The laptop would allow me to download the sitebuilder program that I use to build the History department website and store all the pages on as I work on them to upload whilst at home or in school. This would augment my work at home on this growing project.
We were limited to 300 words, and I don't know yet if I have been successful, but I live in hope!
Obviously I am writing this already having a digital projector and already making extensive use of ICT, so it would be an upgrade option for me, but the thrust is universal. I would also echo what Andrew has put.
"The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts." - Bertrand Russell