Read liner notes from your favorite hip-hop albums and find producers from the best songs. Take note of the things you like about each song's production qualities so you know what to look for in a record producer.
Refer to the yellow pages of your local phone book for area recording studios. Contact them about scheduling a meeting with a producer to discuss your work. Explain the sound you're trying to go for and ask for a sample of their work.
Put an advertisement in your local newspaper. Explain that you're looking for a producer to help with your work. Leave your name, contact information and estimated budget.
Hire an agent to help find the right producer. It is your agent's job to put you in touch with the best available talent. Your album might require several different producers depending how ambitious your record is going to be.