On this site you can find a lot of information about the Dutch town Leiden. The emphasis is on the baptisms before 1812. But some family trees grow because of the additions of others.
When you are searching for a name, consider that the K and C are often used for each other, the same goes for the S and Z.
To search the site you can look here.
Can you use the e-mail address especially for additions and corrections?

For questions about your own family you can use the message board . The more information you give, the bigger the chance you get an answer.
For larger questions (f.i. you want a lot of ancestors) you can contact (for a low fee) Lex.