The Dinosauria include numerous bipedal species, with their large tails often acting as a useful counterbalance to support bipedal locomotion. We all think of sauropods as quadrupeds, which they were. However, their early ancestors were more bipedal, and as their size increased and their structure changed, they eventually became quadrupedal.
Here is a skeleton of Plateosaurus, an early basal sauropodomorph from the Triassic:
Actual Plateosaurus Fossil
And here is an artist's depiction of what a living Plateosaurus may have looked like: Artwork by "dustdevil" from DeviantArt
To learn more about basal sauropodomorphs, visit your local library today. Or just use Wikipedia. That works fine too.