How long for spider eggs to hatch?

It should take a few days or weeks, months at the max.

Improvement: I've been keeping an orbweaver spider for the last week or two and she made her nest about 5 days ago. I'll try and get back to this board when they hatch.

I copied this answer from Yahoo

Most crab Spiders will have two successful hatches of eggs every year. Once the eggs are attached, the female will stay within the vicinity, like you are already observing. The time it takes for the eggs to hatch is based on several parameters, the most important being temperature. The best option in captivity is not to alter the temperature too drastically. Maybe place a small lamp near the eggs and keep them at room temperature, but turn off the light at night to better mimic natural conditions. It could be anywhere from 2 weeks to a month, but probably closer to 2 weeks.

Once the eggs hatch, the young spiderlings are still soft and fragile, and usually will not start eating each other for about 2 days or so....this is not always the case, but as a general rule, they typically need at least a day for their tiny exoskeletons to harden before they start searching for a meal. Your best option is to leave them for a day, and then release them, once outside they will disperse on their own.

You can hold onto your female because she may not be done laying eggs, many spiders are capable of storing sperm for long periods, and she may be able to producer another clutch of eggs, especially since you mentioned she is eating well.