The most popular vendors for cloud PCs are: This is more complex than using a prepackaged service, but you get more control of what hardware you rent and what software you use. It's also possible to 'roll your own' cloud gaming by using a generic cloud PC provider and a streaming solution of your choice. Developments are happening rapidly, so don't be afraid to ask. You are encouraged to do your own research and learn about all your options. Software and services being in the above list is not an endorsement or assurance of quality.
Here are some of the current most popular to get you started: Software and Services
This is a rapidly-developing area and new services and software are coming along all the time. CloudyGamer is for discussing and exploring cloud gaming in all its forms, both self-hosted and all-in-one services.