Well, it does really depend upon where it is found. For example if in C: root...ie c:\i386, then that is likely the i386 folder copied in by someone to save loading the installation cd when, say, running sfc. You can delete that one, noting of course, the caveat i presented.
If it is found in Windows\Driver Cache, then no, don't delete it... this is a backup cache of updates from KBs, or Security etc updates.
If it is in Windows\SevicePackFiles then it contains the files from a ServicePack update eg to SP3. If you need to run sfc to repair system files, or the OS invokes the File Protection System then files from this folder may be required.
Then there is the multitude of i386 folders in ReinstallBackups in system32. These are the older drivers cached after hardware driver updates. Pretty much, if your hardware is working fine currently, then you don't need these.
And if you take any notice of this and your system falls apart, then I cannot be found.