SP Recovery and Clockwork Recovery

I have used SP recovery installable ROMS ever since I rooted. It seems that I will need to flash Clockwork recovery to my phone to install CM.

How do I do that?
How can I switch back to SP Recovery (if I decide to)?

Thanks!

I believe you can download rom manager and click flash clockwork recovery on the top and that's it. Then to go back to sp just flash the alternative recovery at bottom of rom manager.

When I go into Rom Manager, it does not have any alternative recoverys at bottom of rom manager. Is that because I haven't flashed Clockwork yet?

thanks

Yes I believe so. Flash clockwork and it should show up.