Here are the out-of-the-box file types supported by MOSS 2007 Search.

1. ascx   ASP.NET User Control 
2. asp   Active Server Document
3. aspx  ASP.NET Server Page
4. doc   Microsoft Office Word 97 - 2003 Document
5. docm  Microsoft Office Word Macro-Enabled Document
6. docx  Microsoft Office Word Document
7. dot   Microsoft Office Word 97 - 2003 Template
8. eml   Internet E-Mail Message
9. exch  exch document
10. htm   HTML Document
11. html  HTML Document
12. jhtml jhtml document
13. jsp   jsp document
14. mht   MHTML Document
15. mhtml MHTML Document
16. msg   Outlook Item
17. mspx  mspx document
18. nsf   nsf document
19. odc   Microsoft Office Data Connection
20. php   php document
21. ppt   Microsoft Office PowerPoint 97-2003 Presentation
22. pptm  Microsoft Office PowerPoint Macro-Enabled Presentation
23. pptx  Microsoft Office PowerPoint Presentation
24. pub   Microsoft Office Publisher Document
25. tif   tif document
26. tiff  tiff document
27. txt   Text Document
28. url   Internet Shortcut
29. vdx   Microsoft Visio Document
30. vsd   Microsoft Visio Document
31. vss   Microsoft Visio Document
32. vst   Microsoft Visio Document
33. vsx   Microsoft Visio Document
34. vtx   Microsoft Visio Document
35. xls   Microsoft Office Excel 97-2003 Worksheet
36. xlsm  Microsoft Office Excel Macro-Enabled Worksheet
37. xlsx  Microsoft Office Excel Worksheet
38. xml   XML Document