I would be way soaking them for 24 hours. Some citrus don't take well to it, particularly mandarins and oranges, and soaking for too long can increase chances of fungal rot. Best to soak overnight if the seeds are dried (which decreases chance of germination greatly) or even better, wash straight from fruit and plant.

Providing bottom heat speeds up germination. I know some people who put the tray/pots on their computer monitor which stays on, or in the boiler cupboard. I just bought a heated propagator from B&Q for about £14 and it works great.

Citrus can take up to 3 months to germinate - longer if the conditions aren't right. The seeds shouldn't be kept wet, only damp. When they start to grow, they should be kept in good light, and when they get first set of leaves (not the first two that pop out of the soil, but the next set) fertilize with a weak, half strength fertilizer.

I realise its been a while since the original thread was posted, but hopefully this thread will benefit others Would be nice to see some results if the original poster is still around!

As for time to fruiting, patients is required. With key limes, 2-3 years is normal, though I know someone who's flowered and fruited at just over a year. Mandarin should take around 3-5 years, lemons about 5-7. Oranges about 5-7. Grapefruit...the easiest to grow, can take up to 25-30 years! They need a massive node count to flower, and this usually cannot be obtained when they are container grown, which is a shame!