The most useful and independent advice that I can suggest is here Tiggy.
http://www.businesslink.gov.uk/bdotg/action/la yer?topicId=1073864308&r.s=sl
Business Link is a non-profit organisation run through Government. I suggest you have a read then ask us more questions if you need to.
Tax is covered in it - basically each partner deals with his/her own tax affaris as if he/she is self-employed. There are no tax advantages in doing it - just a sharing of resources, knowledge and skills to help with running the business. There are downsides too - if the partnership falls apart what happens? - these are best sorted upfront through some form of partnership agreement that set-out the 'rules'. These rules are designed by the partners themselves.
Most partnerships would set up a business bank account in the name of the partnership and buy materials through that.