If you’re interested in improving the scientific content of wikipedia, there are several places you can start:

• This List of Fellows of the Royal Society by year shows which scientists have biographies and which don’t . If you click on a year, take 2012 for example, any red links show which people do not yet have wiki-biographies
• The Wikpedia Project Royal Society outlines some work done at the Royal Society
• The Wikipedia Project Biography (Science & Academia) lists biographies that need creating or improving

If you haven’t edited wikipedia before, Darren Logan’s introduction to editing wikipedia for scientists is a good place to start.