are you using t*s*m*c process?
that's no way to design a "perfect" VCO, but only fit to the specification.
Since the VCO is for 802.11b, should it be 2.45GHz or multiple of it. In this case, you should use LC VCO for its low-phase noise and high prefequency performance.
To start the design, you should have the relevant components,
1). on-chip inductor (spiral inductor),
2). variable capacitor (varactor, either pn-diod or mos varactor),
3). negative resistance device, (MOS),
The design step,
1. determined the L, C values, but need to refer to the inductor and varactor available,
2*pi*f=1/sqrt(L*C);
2. estimate the impedance of the LC tank, which is needed to compansated by the negative resistance,
3. with the desired voltage swing, the current needed can be obtained,
Are you using @ds for simulation? It is much better than s/p/e/c/t/r/e. refer to the mos_vco_prj under the example.