No, you will not be able to take your exam online at any time. There must be 3 fully accredited VE's (FCC Volunteer Examiners) present to supervise and score your completed written examination. There are no short-cuts to this process. There are, however, online study programs which you can use, some of which are free of cost. Those free programs do not help you focus on your weaker study points to help you bring those to become strength study areas. I have used both the free program and, in June 2012, switched to a pre-paid, online study program. That program can be accessed at:
http://www.hamradiolicenseexam.com. The program owners guarantee to refund your money if you do not pass the examination and... they stand behind that promise. In a 70 hour study period, over a six week period, I passed both the General and Extra Class FCC exams with flying colors. I am now a fully accredited ARRL VE. The best study results occur when the individual studies DAILY in two separate 30 minute sessions. I also used the Gordon West FCC exam study guides along with the online program. I used those study guides for all three FCC ham radio license classes. Received my technician class license 3 years ago and, I'll be 75 this coming December 2012.
73, W6LDP