First college acceptances are coming in!
College Board (US Colleges)
UCAS Search Tool (UK universities, choose ‘undergraduate’)
Application Portals (student)
The Netherlands (except for some University Colleges)
Common Application (USA's most common portal, but there are also individual university sites, etc.)
UCAS Apply (UK)
Other countries: see individual university websites
Financial Aid for U.S. Colleges
FAFSA (US Citizens only)
This is by no means exhaustive, many universities keep adding programs all the time, so check out the websites of universities you may want to attend to see what they offer in the summer. Also see your counselor for recommendations based on your particular interests.