My friend told me it is better to take the test in February vs. October/December. Is that true?
no. not true.
Exactly. The test is standardized, which means that the test normed. This means that they are statistically balanced by a group of highly specialized statistical psychologists called 'psychometricians'. These psychometricians make sure that each test has the same basic difficulty level as all the others, and balance out tiny differences by adjusting the scale accordingly.
Your friend's advice was probably based on the fact that February has the fewest number of test-takers. However, the number of test-takers will have exactly ZERO effect on your performance or on how the test is scored, because the scale is essentially set before the test is ever administered.
The best time to take the test is once you've thoroughly studied and prepared. There's no strategic advantage to be gained by taking it in February (or any other time), although certain administrations can be too late in the cycle for applications. (For example, February 09 will be too late in the fall 09 application cycle and would hinder your chances at being accepted to many schools. Also, the December test can be too late in the cycle for the early admission options at some schools.)