Students interested in applying to the Gettysburg X-SIG Summer Research Program (sponsored by the Kolbe, Dickinson, Albaugh, Alberte, and Peterson Funds) can read about the program and view deadlines here.
Summer research programs are competitive, requiring you to plan ahead to submit an effective application. With many application deadlines in December or January, you should being searching for opportunities in the Fall semester. Several resources and summer research search engines are below, but a surprising number of students find their internships through Google searches and word of mouth, so be sure to ask faculty and fellow students about opportunities. You will need at least one letter of recommendation from a faculty member; be sure to ask early.
The national Science Foundation's Research Experiences for Undergraduates (NSF-REU) program supports active research participation by undergraduate students in any of the areas of research funded by NSF. REU projects involve students in meaningful ways in ongoing research programs or in research projects specifically designed for the REU program with a large number of research opportunities through its REU Sites program. An REU Site consists of a group of ten or so undergraduates who work in the research programs of the host institution. Each student is associated with a specific research project, where he/she works closely with the faculty and other researchers. Students are granted stipends and, in many cases, assistance with the housing and travel. Undergraduate students supported with NSF funds must be citizens or permanent residents of the United States or its possessions. An REU Site may be at either a US or foreign location.
Students apply directly to REU Sites or to NSF-funded investigators who receive REU Supplements. To identify appropriate REU Sites, students should consult the directory of active REU Sites at https://www.nsf.gov/crssprgm/reu/reu_search.jsp where you can search by discipline, location, or keyword.
The Institute for Broadening Participation has a mission to increase diversity in the Science, Technology, Engineering and Mathematics (STEM) workforce and their website is a fantastic resource for finding paid summer research programs for undergraduates - try here.