Your Question does not make sense to me. Ohms is a unit of measure for resistance or impedance.
The resistance from the grounded portion of a receptacle to the equipment ground that connects to it should be zero (there will be some actual resistance, but it will be too small to measure with most measuring devices).
The NEC does not specify a value for this, but requires "...a permanent, low-impedance circuit capable of safely carrying the maximum ground-fault current likely to be imposed on it...". This information can be found in the 2002 NEC, article 250.4(5). The NEC is also known as NFPA 70, National Electrical Code (published by the National Fire Protection Agency).
The equipment grounding conductor resistance is not a valid method of determining the validity of the ground-fault path between the recepacle and the overcurrent device. A test instrument for evaluating the validity of the equipment ground should be performance oriented and will impose a load on the equipment ground that is sufficient to actuate the overcurrent device.
A 'Sure-Test' tester will check the integrity of the grounding resistance. According to there liturture ' IEEE recomends that the conductor resistance of the conductor not exceed .25 ohms..' If the resistance is higher than 2.0 ohms it will read high, and at that point it would take about 90 seconds to trip a breaker.