Caitlin passed on this reminder:
I thought it might be important to note that REU deadlines are usually between the second week of January and early March.
REU stands for Research Experience for Undergraduates and is an NSF funded program that is one of the largest sources of funding for undergraduate summer research. You apply to the individual REU sites for the funding so you need to do your homework.
Access the full list of REU sites here for Biological Sciences and here for a wider list of subjects.
Click on the individual sites to find full details and application details.