Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007;
root:xnu-792.24.17~1/RELEASE_PPC

Python 2.5.2 (r252:60911, Feb 22 2008, 07:57:53) 
[GCC 4.0.1 (Apple Computer, Inc. build 5363)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import os, sys, locale
>>> locale.getpreferredencoding()
Bus error

Sample crash report excerpt follows (plenty more available on request!).
Note that the version of python given in the crash report is *not* the
same as the version of python actually in use. I have never had an alpha
version of python installed. The current version is the standard version
of 2.5.2 available as a dmg download from python.org i.e. the universal
framework build for 10.4.

OS Version:     10.4.11 (Build 8S165)
Report Version: 4

Command: Python
Path:   
/Library/Frameworks/Python.framework/Versions/2.5/Resources/Python.app/Contents/MacOS/Python
Parent:  bash [27154]

Version: 2.5a0 (2.5alpha0)

PID:    4692
Thread: 0

Exception:  EXC_BAD_ACCESS (0x0001)
Codes:      KERN_PROTECTION_FAILURE (0x0002) at 0x00000000

Thread 0 Crashed:
0   com.apple.CoreFoundation 	0x907beac0 CFStringGetCStringPtr + 408
1   _locale.so               	0x000f1cd8 PyLocale_getdefaultlocale + 328
(_localemodule.c:435)
2   org.python.python        	0x002b393c PyEval_EvalFrameEx + 17036
(ceval.c:3557)
3   org.python.python        	0x002b5e50 PyEval_EvalCodeEx + 2096
(ceval.c:2836)
4   org.python.python        	0x002b3f48 PyEval_EvalFrameEx + 18584
(ceval.c:3669)
5   org.python.python        	0x002b5e50 PyEval_EvalCodeEx + 2096
(ceval.c:2836)
6   org.python.python        	0x002b5ff0 PyEval_EvalCode + 48 (ceval.c:500)
7   org.python.python        	0x002dbb24 PyRun_InteractiveOneFlags + 772
(pythonrun.c:1274)
8   org.python.python        	0x002dbd30 PyRun_InteractiveLoopFlags +
288 (pythonrun.c:725)
9   org.python.python        	0x002dc3f0 PyRun_AnyFileExFlags + 176
(pythonrun.c:693)
10  org.python.python        	0x002eba9c Py_Main + 3052 (main.c:523)
11  org.python.python        	0x000019bc 0x1000 + 2492
12  org.python.python        	0x000016c0 0x1000 + 1728

Thread 0 crashed with PPC Thread State 64:
  srr0: 0x00000000907beac0 srr1: 0x000000000000d030                    
   vrsave: 0x0000000000000000
    cr: 0x84244224          xer: 0x0000000020000004   lr:
0x00000000907be930  ctr: 0x00000000907be928
    r0: 0x00000000a07bb678   r1: 0x00000000bfffd3a0   r2:
0x00000000a07bb278   r3: 0x0000000000000000
    r4: 0x0000000000000000   r5: 0x00000000bfffd2e0   r6:
0x0000000000000005   r7: 0x0000000000000007
    r8: 0x0000000000702333   r9: 0x000000000000001c  r10:
0x0000000090bb4bb8  r11: 0x00000000000f33d8
   r12: 0x00000000907be928  r13: 0x0000000000058b24  r14:
0x0000000000071e40  r15: 0x000000000006aa20
   r16: 0x0000000000000000  r17: 0x0000000000000001  r18:
0x00000000000732a8  r19: 0x0000000000619410
   r20: 0x0000000000000000  r21: 0x000000000006a9b0  r22:
0x0000000000000000  r23: 0x0000000000058b39
   r24: 0x00000000000f1b90  r25: 0x00000000006001d0  r26:
0x000000000007e300  r27: 0x0000000000000000
   r28: 0x0000000000000000  r29: 0x00000000a07bbb6c  r30:
0x0000000000000000  r31: 0x00000000907be930

Binary Images Description:
    0x1000 -     0x1fff org.python.python 2.5a0 (2.5alpha0)
/Library/Frameworks/Python.framework/Versions/2.5/Resources/Python.app/Contents/MacOS/Python
   0xa2000 -    0xd9fff readline.so 
/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/lib-dynload/readline.so
   0xf0000 -    0xf2fff _locale.so 
/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/lib-dynload/_locale.so
  0x205000 -   0x323fff org.python.python 2.5a0 (2.5)
/Library/Frameworks/Python.framework/Versions/2.5/Python
  0x705000 -   0x74afff libncurses.5.dylib 
/Library/Frameworks/Python.framework/Versions/2.5/lib/libncurses.5.dylib
  0x7de000 -   0x7e1fff operator.so 
/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/lib-dynload/operator.so
0x8fe00000 - 0x8fe52fff dyld 46.16	/usr/lib/dyld
0x90000000 - 0x901bcfff libSystem.B.dylib 	/usr/lib/libSystem.B.dylib
0x90214000 - 0x90219fff libmathCommon.A.dylib 
/usr/lib/system/libmathCommon.A.dylib
0x907bb000 - 0x90895fff com.apple.CoreFoundation 6.4.11 (368.35)
/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation
0x908e0000 - 0x909e2fff libicucore.A.dylib 	/usr/lib/libicucore.A.dylib
0x90a3c000 - 0x90ac0fff libobjc.A.dylib 	/usr/lib/libobjc.A.dylib
0x90aea000 - 0x90b5afff com.apple.framework.IOKit 1.4 (???)
/System/Library/Frameworks/IOKit.framework/Versions/A/IOKit
0x90b70000 - 0x90b82fff libauto.dylib 	/usr/lib/libauto.dylib
0x90b89000 - 0x90e60fff com.apple.CoreServices.CarbonCore 681.17
/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/CarbonCore.framework/Versions/A/CarbonCore
0x91111000 - 0x9111ffff libz.1.dylib 	/usr/lib/libz.1.dylib
0x91122000 - 0x912ddfff com.apple.security 4.6 (29770)
/System/Library/Frameworks/Security.framework/Versions/A/Security
0x913dc000 - 0x913e5fff com.apple.DiskArbitration 2.1.2
/System/Library/Frameworks/DiskArbitration.framework/Versions/A/DiskArbitration
0x913ec000 - 0x913f4fff libbsm.dylib 	/usr/lib/libbsm.dylib
0x913f8000 - 0x91420fff com.apple.SystemConfiguration 1.8.3
/System/Library/Frameworks/SystemConfiguration.framework/Versions/A/SystemConfiguration
0x91433000 - 0x9143efff libgcc_s.1.dylib 	/usr/lib/libgcc_s.1.dylib
0x945e4000 - 0x94604fff libmx.A.dylib 	/usr/lib/libmx.A.dylib

I have got as far as I can tracking this issue down but would be happy
to provide further information if somebody would give me (a pointer to)
instructions or a hint.