I have Leopard loaded but have not upgraded to Lion. I want to use iCloud but can I wait for the next upgrade, miss out on Lion and still get the software for iCloud?

iCloud will be present in Mountain Lion, the version of OS X that will replace Lion sometime this summer. You will still need to have at least Snow Leopard 10.6.8 installed to purchase Mountain Lion from the App Store.

First off your signature is impossible. 10.6.8 will not run on any Powerbook, let alone Lion (10.7). 10.6.8 is Snow Leopard, and not Leopard. iCloud options for those still stuck with 10.5 or 10.6 are listed below:

https://discussions.apple.com/docs/DOC-2551

Windows compatible with iCloud will not run on Powerbooks, but will on MacBooks, MacBook Airs, and MacBook Pros. No one knows if waiting for Mountain Lion will offer any better chances. And while many have hoped for a 10.6.9 compatible with iCloud since 10.7's release, no info has ever officially materialized that it would ever exist.

Some additional notes:

Powerbooks max out on 10.5.8 (Leopard)

MacBook/Pro with just CoreSolo or CoreDuo can't run 10.7 (Lion) or higher, however can run a version of Windows compatible with iCloud,

and are stuck with 10.6.8 Snow Leopard as their highest Mac OS X.

MacBook/Pro/Air with Core2Duo or higher are able to run Lion and get the full compliment of iCloud features without Windows.

Mountain Lion's system requirements are not yet officially known.