This article describes a 900 MHz oscillator which scales nicely into 300 MHz.... easy to build and should provide very little troubble **broken link removed**
That said, you did not tell us your need, wide band or narrow band, high performance or simple design!
If you narrow your request we will be able to provide more precise information!
I use it to generate clock signal for IC chip, so I am mainly concerned with its stability. Can you give some examples that are reliable and stable to work?