Well, not forever perhaps.
by MarkFlax - 7/10/10 4:20 AM
In Reply to: Will existing updates and service packs remain available? by jcbowen
But for years to come, yes. The change is that 'Support' from Microsoft will no longer be available for SP2 and previous users. That's different.
Have you considered another option? Have a look at XP slipstreaming SP3 in Google or your favorite search engine.
This makes a copy of your XP original setup disk, and adds to it all the SP3 updates. Since SP3 includes all the previous SPs, that might be a quicker way to reinstall when necessary.
Hope that helps.