Compilations:

• from  the AAS.
• a huge compilationcourtesy of Penn State; some listings may be out of date.
• A more current listing courtesy Harvard/CfA.

Direct Links
The following all have summer research programs for undergraduates - any experience like this is highly recommended. These institutions usually offer housing and a modest stipend, though not all. This list covers astronomy and planetary science opportunities, but there are many more in other fields.

• Kitt Peak National Observatory,Tucson AZ
• National Solar Observatory, Sunspot NM
• Space Telescope Science Institute, Baltimore MD
• Northern Arizona University & Lowell Observatory, Flagstaff AZ
• Mt Wilson Observatory, LA, CA
• National Radio Astronomy Observatories, VLA (NM), Greenbank (WV)
• Maria Mitchell Observatory, Nantucket Island, MA
• Cornell University (Planetary Astronomy)
• Harvard-Smithsonian Center for Astrophysics (Cambridge, MA)
• Carnegie Institution (Geo- and Cosmo-chemistry)
• Lunar & Planetary Institute, Houston TX
• Haystack Observatory (MIT) (radio astronomy)
• NASA Planetary Geology & Geophysics (at many universities & labs, apply through University of Buffalo)
• Bucknell

Most have deadlines in January and February!!!!

Please let me know if this information has helped you.