Howto write a letter(s) to ask for, Spnsorship, donations and/or other Contributions for raising fund for LGBT Pride

I am looking for someone o help me write a letter inviting companies to sponsor, donate or generate some other type of involvement that couldl help raise funds for our Aberdeen Pride event for 2009 in August. The idea of Pride is to make aware of issues that relate to individual mainly in the gay community hoever not aways;

Such as ;

1. Sexual health awareness
2. homphobia and discrimination in all areas of enviroment
3. Sense of Community of one and other
4. Promoting intergration amoungst the wider community
5. raise awareness of all issues that concearn different individuals within the LGBT communtiy
6. Raise money for Terrance Higgins Trust

The event is hopefully a whole week the will show Parade,stalls, markets, information sites and entertianment; comedy, music, live bands, stand - up, inovated speachs etc, that will keep the supporters and others that are interested in the topic that we hope to bring to the surface.

There is an estatmated value to cover the cost of £30,000 (this could be more) that will cover all expenses for the day event and the other long week events, covering audio, visual, security, isurance, Stage & PA hire, Marquee Hire, Marketing and Publicity, Artist Fees, Toilet Hire, Generator Hire, Ambulance and other stationary applications

Please help, something I do not how to put in an attract way that can beneit the companies in sales and publicity; ideas of companies would range from;

1. Super-stores
2. Clothing retialers
3. Traveling Agents
4. Jewllers
5. Banks
6. Car Dealers
7. Loan Companies
8. Chain Pubs
9. Radio
10. Hotels
11. Gyms
12. Restaurants/ food store
13. Cinema
14. Haridressers and beauty Salons
15. Diageo
16. Belhavean etc.

All help would be obliged.

Thanx Scotland