The first number would be truly random - at least as random as the external source. The following numbers in the series would not, however.
If you want a "more random" seed than Millisecs(), you can add user input. Most of the time, the player will take a different number of milliseconds to press a key after the game has started. Multiply that by Millisecs() and you've got a much better seed.
The standard C rand() - as used by Blitz I think - isn't terribly good at distributing random numbers though. If you need something awesome, look into the Mersenne Twister.
If you want a "more random" seed than Millisecs(), you can add user input. Most of the time, the player will take a different number of milliseconds to press a key after the game has started. Multiply that by Millisecs() and you've got a much better seed.
The standard C rand() - as used by Blitz I think - isn't terribly good at distributing random numbers though. If you need something awesome, look into the Mersenne Twister.