Questions about legal forms, contracts, etc.

Hi everyone,

I am going to start selling my Internet Marketing services to local businesses in the area. I live in the United States. I'll offer services like the following:

- Setting up hosting and domain name
- Installing blog/site
- Installing email capture service
- Setting up newsletters for subscribers
- Installing Google Analytics
- Running AdWords campaigns
- Forums setup
- Tons of other Internet Marketing stuff...

I will have two main types of service available:

- Continuous support where I am paid monthly to maintain the website, perform frequent SEO-related tasks to help ranking, etc.
- One-time installation where I am paid in one large sum but there is no further support after services are rendered

Here are my questions:

1. Do I need a legal contract signed by the client and myself?

2. If I get paid by PayPal, cash, or check, what do I need to save/track for when tax season comes around? (I understand if this question cannot be answered here.)

3. If I end up outsourcing some (or eventually most) of the services I offer, do I have to tell the client? (This includes things like logo design, heavy customization to the sites, website maintenance, backlinks generation, etc.)

I'm sure I will have more questions soon! This is a fun project and I'd like to get it going as soon as possible. I appreciate any responses with answers, tips, advice, feedback, and criticism!

Thanks,
Nick