PANAMA - *Passport, tourist card or visa and onward/return ticket required. Tourist card valid 30 days, available from airline serving Panama for $5 fee. Stay can be extended up to 60 days, apply at the main office of Immigration and Naturalization in Panama. Visa requires 1 application form and 1 photo. Allow one working day for processing. For longer stays and additional information regarding travel other than via a commercial airline, contact Embassy of Panama, 2862 McGill Terrace, N.W., Washington, D.C. 20008 (202/483-1407) or the nearest Consulate: CA (415/391-4268), LA (504/525-3458), NY (212/840-2450) or TX (713/622-445l).This information comes from http://travel.state.gov/foreignentryreqs.html
COLOMBIA - *Passport, proof of onward/return ticket, and entry permit required for tourist stay. Entry permits are granted by the immigration authorities at the port of entry, for an initial stay of up to 90 days, extendable for multiple additional periods. Minors (under 18) traveling alone, with one parent or in someone else's custody, must present written authorization signed before a notary and authenticated by the Colombian Consulate from the absent parent(s) or guardian. Persons suspected of being HIV-positive may be denied entry. For information about longer stays, business or official travel contact Embassy of Colombia (Consulate), 1825 Conn. Ave., N.W., Suite 218, Washington, D.C. 20009 (202/332-7476) or nearest Consulate General: CA (213/382-1137 or 415/495-7191), FL (305/448-5558), GA (404/237-1045), IL (312/923-1196), LA (504/525-5580), MA (617/536-6222), MN (612/933-2408), MO (314/991-3636), OH (216/943-1200 ext. 2530), NY (212/949-9898), PR (809/754-6885), TX (713/527-8919), or WV (304/234-8561)
For nationals of other countries, check The Columbian Consulate.
But Benj, Michelline, Ole, Brigitta, you don't seem to need visas for Colombia.
As far as Panama, I can't find a page for it. If anyone else can, send it to email@example.com.