They are listed on Graviex.net: https://graviex.net/markets/zacabtc?markets=all&column=name&order=asc&unit=volume

Prequisites for a masternode are:
- min. 1000 ZACA
- 1,5GB storage
- White static IP with open ports for masternodes

I suggest you to use an Ubuntu VPS, since there are some bugs with windows.