Nice job! As a US-based consultant, I've found it's always best if you immediately suggest a contract. This way you can ensure it starts with terms favorable for you.

I've also found it's pedagogically helpful to have two versions of each contract, a consultant-favored and consultee-favored. This way you can understand how each clause may be tweaked to benefit each party. For example, this book does this (US-based): https://www.amazon.com/Consultant-Independent-Contractor-Agr...

I enjoyed the NOLO book "Consultant & Independent Contractor Agreements": https://www.amazon.com/Consultant-Independent-Contractor-Agr... (look up the prior editions for reviews)

The majority of the book is agreement templates, including one for software development. But more importantly, it walks through the language and what you should be looking for -- interestingly, both from the perspective of an employer and contractor. Of course, it's also helpful/recommended to get feedback from a lawyer for your specific situation.

http://www.amazon.com/Consultant-Independent-Contractor-Agre...

http://www.amazon.com/Service-Agreements-SMB-Consultants-Ser...

Start here:

Software Development: A Legal Guide

http://www.amazon.com/Legal-Guide-Software-Development-CD-Ro...

and

Consultant & Independent Contractor Agreements

http://www.amazon.com/Consultant-Independent-Contractor-Agre...

both by: Stephen Fishman J.D : NOLO press