Chart of  Transmission Media and the Electromagnetic Spectrum (from William Stallings, Business Data Communications, fourth edition by William Stallings.  Prentice Hall, 2001, page 157).

Note:  You can locate your cell phone or favorite radio station on the spectrum.
       A cell phone frequency of 900 MHz is close to 1,000 MHz = 10**9 Hz.  It would be under the column labeled UHF.
       FM radio station numbers are in MHz.  So 104.1 FM would be at 104.1 MHz which is just about 10**8 Hz.
       AM radio station numbers are in KHz.  So  740 AM would be at 740 KHz.  This is about 1000 KHz = 10**6 Hz.
For more on info on where the many wireless devices we have today fit into the electromagnetic spectrum, read a concise article on the Radio Spectrum  at howstuffworks.com.