From what I've been reading lately you now need plane tickets and hotel reservations in order to apply for a Chinese visa. Suggest checking the embassy web site.

I've been to mychinavisa.com, travisa and the embassy site. No mention of needing reservations and no space on application to put that info.

This form seems to indicate that the countdown starts with the date of application (look at section 2.2):

http://www.china-embassy.org/eng/ywzn/lsyw/vpna/news/W020110113222979154291.pdf

Note it also asks where you will be staying in China. Are you looking at the latest form?

They ask where you'll be staying, but you don't need to provide reservations for any hotel. No plane tickets required either. But others are correct, the valid period starts from application date. You can't request a later date. So, first decide when you want to go first.

I got my visa to China last August. It's good for one year from the date of issue. There are several agencies available that can get your visa for an extra cost. The cost is based on depending on how fast you need the visa expedited for your trip. It's a 2 page application form that was begun last June, replacing the older form asking questions about which hotel etc. The new application is much simpler and faster. The cost for a one year, three [ I believe] entrance visa costs $140 plus the agency fee.

The visa can be obtained directly also from a Chinese Consulate visa office in Wash. DC and NYC and LA I believe. We went to Washington DC to obtain ours in person. It took the better part of a day but we were fortunate to be able to fly to DC and pick it up the same day. You do need passport size photos for the visa. However, the office in DC was taking pictures of people for the visa who did not bring photos with them. This is a small addiional coist.

The visas are given out when the govermant announces it in the afternoon . The people who came from the various agencies seemed to know the staff and appeared reliable as they had bundles of visa apps that they gave to the consulate staff in the morning and received them back in the afternoon.A word of caution however, make sure if you use an agency that the application is filled out completely as asked by the govt. or it may be returned.
We were in Beijing, the Great Wall, it was an experience that was wonderful. Enjoy your trip.

The visa requirements vary depending on your country of origin.
A three-month visa means that you must enter China before three months after it was issued (expiry date). You can stay in China beyond the expiry date. It is actually referred to as "the last date at which you can enter China". You can then stay as long as you are allowed in your visa, usually 30 to 90 days.

Very lately I've been reading that the application process has been revamped and is no longer handled by embassy consular services. Processing seems now to be farmed out with a much longer form and yes, hotel and flight information required making it trickier for independent travelers. I haven't yet applied for a visa under the new regulations but any of the consulate websites should point one to the correct agency and the new form.

MmePerdu - as I mentioned, the requirements vary depending on where you are and what passport you hold. we cannot make general statements about the process without knowing this information. Applying in the UK is not at all the same as applying in the US for example.