Taking pics of games and flash help!

Hey folks,

Is there a tutorial for shooting Football games night/day and volleyball games?
I have a Canon REBEL XTi.

From my understanding, I heard of going with 1/300 shutter speed and High ISO like 1600? True or not? Recommendations?

Do you recommend I purchase a new flash rather than the stock flippy one?

Recommendations on flashes I could purchase?

Thanks.

I have a stock 18-55mm and a 100-300mm lens

Flash is usually not appreciated at volleyball games and as for football, I rent fast lenses for playoff games. IME flash really isn't very effective in many situations unless you have multiple remote flashes. What I use are fast lenses + higher ISO's.

85 1.8@f2 will be your best buddy for volleyball, anything slower than f2 will give you less than 1/400s at iso 1600. for football, 70-200 is nice on a 1.6 crop, and f2.8 version should be fast enough for 80% of the nighttime action, and 100% of the daytime stuff. also works decently for volleyball

The two main sports ive bin shooting .
I use a 70-200 F/2.8 for both, most of the time. I also use a 24-70F/2.8 for volley ball
Night football you will definatly need a Fast lense (70-200mm F/2.8)
Day time you should be find with your 100-300mm
Volleyball, well if your not going to use flash a fast lense is a must also.
I actully use 2 flashes hooked up threw pccket wizards and havent gotten any complaints about flashing.

Thanks alot guys!