Mozilla is looking to crash-proof future versions of its Firefox browser by developing a new feature called Electrolysis that will compartmentalize processes on a tab-by-tab basis -- similar to Google Chrome. But that's not the only angle they are taking. Also like Chrome the just-released Firefox 3.7 alpha 2 (which will actually be released as 4.0) has added out-of-process plug-in support, allowing Flash and the like to run in a separate memory compartment so that the browser can gracefully handle any crashes instead of going under itself.
Those interested in giving the new features a go and reporting back to Mozilla can use the links below to download. Mac support for out-of-process plug-ins is not available yet, however. Keep in mind that this is a very early preview intended for developers only and should not be used as your primary browser.