Just import the private key into the bitcoin client

do this for every private key and it will all end up in the same wallet.dat


there are lots of tutorial on how to import a private key, and it varies between bitcoin clients


eg

 Run Import Command in Debug Window

In the console at the very bottom is a text entry box. In here enter:

importprivkey yourPrivateKeyInWalletImportFormat "TheLabelThatIWant"

then wait a while - it takes a few minutes to complete

https://en.bitcoin.it/wiki/How_to_import_private_keys_v7%2B

http://brainwallet.org/
How can I turn the details from this website into one "wallet.dat"?
https://translate.google.com.hk/?q=如何将这网站中的内容，变成wallet.dat文件&um=1&ie=UTF-8&hl=zh-CN&sa=N&tab=wT#auto/en/%E5%A6%82%E4%BD%95%E5%B0%86%E8%BF%99%E7%BD%91%E7%AB%99%E4%B8%AD%E7%9A%84%E5%86%85%E5%AE%B9%EF%BC%8C%E5%8F%98%E6%88%90wallet.dat%E6%96%87%E4%BB%B6
Above this is the translation from one of my friend, and the following is my original text