Summer research opportunities are often advertised on the SIGCSEemail@example.com email list or directly to department chairs. Consider advertising to other nearby institutions or CRA member institutions.
Mentors can consider participating in the CRA-WP Distributed Research Experiences for Undergraduates (DREU) program. The objective of this program is to increase the number of women and underrepresented groups entering graduate studies in the fields of computer science and engineering.
The National Science Foundation (NSF) also sponsors and publicly announces REU sites, which is a great way to recruit many students to a group a faculty.