I can't remember seeing a Buzz character around the park, but there is a Toy Story-themed pizza restaurant in Discoveryland. This is (was?) called Buzz Lightyear's Pizza Planet. It is a large warehouse-like building serving pizzas, burgers and salads. It has a nice indoor play area, with a ball pit, slides, climbing nets, etc. It includes a large Buzz Lightyear model to clamber over.
Regards
Rob