You make the un-numbered pages a distinct section, then number the pages in the section after it, this way: (Note: This answer is long because it contains two sets of instructions: One for Word 2007 and one for previous versions.)
In Word versions earlier than Word 2007:
1. At the top of the first page you want numbered, click the Insert->Break menu item.
2. Insert a Next Page type section break.
3. Move the cursor down a few lines so it's in the new section you just created.
4. Click on the View->Headers and Footers menu item. You should now see and be able to edit the section's header.
5. One of the icons on the Headers toolbar that pops up, probably the fifth from the right, will say "Same as Previous" when you hover the cursor over it. Click it to disconnect the header from the previous one.
6. The one to its right will say "Switch between Header and Footer" Click it.
7. You're now in the footer. Repeat step 5.
8. A third icon, probably the one to the right of the Switch one, will say "Move to Previous" Click it. You've now moved to the footer of the first section.
9. If there's a page number in the header or footer for this section, delete it.
10. Close the toolbar.
11. Go into the second section.
12. Click on the Insert->Page Numbers menu item.
13. Click on the Format button.
14. If you want the first section’s page numbers to count but not show, click Continuous.
15. Or, if you want the page numbering to start at one, click Start At. A 1 should show up in the list box adjacent to it.
16. Click OK.
17. Click OK to actually insert the page number.
In Word 2007:
1. Click at the top of the first page you want numbered.
2. Click the Page Layout tab on the Ribbon.
3. Click the Breaks icon in the Page Setup group.
4. Insert a Next Page type section break.
5. Click on the Insert tab on the Ribbon.
6. Click the Header icon and select Edit Header.
7. Deselect Link To Previous in the Design tab that appeared on the Ribbon.
8. Go back to the Insert tab and repeat Steps 5 to 7 for the Footer.
9. If there's a page number in the header or footer for the first section, delete it.
10. Go into the second section.
11. On the Design tab again, click the Page Number icon
12. Click Format Page Numbers.
13. If you want the first section’s page numbers to count but not show, click Continuous.
14. Or, if you want the page numbering to start at one, click Start At. A 1 should show up in the list box adjacent to it.
15. Click OK.
16. Click OK to actually insert the page number.
That should do it. What you now have is two sections. Both sections have headers and footers, but the page number will appear only in the second section.
Hope that helps.