Hi,
I'm sure others will say similar things, but it depends on what kind of project you do, and in what field. My research projects I did as an undergrad (in astronautical engineering and mol. biology) took an average of 30-50 hrs/week, depending on the week. 🙄 But it totally depends on your project. At my school, you interviewed for projects w/ PIs, post docs, etc. just like a job interview and you could find out what kinds of hours were expected of you...but as you'll soon find out, research doesn't always go as planned 😉 and you may find yourself in unpleasant situations.
My advice? Find professors at your school (or elsewhere) who are researching in fields that interest you and are looking for undergrads to contribute. Then contact those people (often requires sending a cover letter and CV/resume...) and let them know of your interest. And find out what is required of you in terms of skills required, hours, etc.
Good luck!