To make sure you have enough time to prepare, please apply the visa as early as you can. For most attendees, it is easier to apply for a Tourist ("L") visa; an invitation letter is NOT required for obtaining a Tourist visa.

When entering mainland China you’ll need a pre-arranged visa (unless you’re from Japan, Brunei, or Singapore) which you can arrange at a Chinese embassy or consulate anywhere in the world. The most commonly issued visa is an L (Tourist) Visa which is valid for a duration scaling from 30 days to one year for visitors. Prices are always fluctuating but expect to pay between $60-$130 depending on current rates and your nationality. Other types of visas include:

• F (Short term work) Visa – Designated for business trips, interships, or short study. You’re formally required an invitation letter however you can bypass this stipulation by getting the visa in Hong Kong or Macau from one of many travel agencies.
  
• Z (Long term work) Visa – Multiple-entry, long duration visas which are for people employed full-time in China. Requires a lot of paperwork and a hospital visit for a physical examination.
  
• X (Student) Visa – Six month, one-year, or longer duration depending on the length of your study commitment.
• L (Tourist) Visa – 30 to 90 day durations, generally for multiple entry, from anywhere from one year to ten years, depending on your nationality and the type of visa which you request. The length of your tourist visa will depend on your specific circumstances, and luck is often a factor.

With the visa rules and regulations changing as often as they do, you’re best off contacting a Chinese consulate directly to make sure you’re getting totally accurate information. To give you an idea of the fluctuations, a year ago tourist visas weren’t being issued and now they’ve resumed operation including up to one-year duration.

For more information check the Chinese Embassy website in your country.