If you're using 5.8.x, it is available via PPM from the Active State repository: 

c:\test>ppm-shell
ppm 4.05 (ActivePerl 826)
Copyright (C) 2009 ActiveState Software Inc.  All rights reserved.
ppm> search Math::GMP
1: Math-GMP
   High speed arbitrary size integer math
   Version: 2.04
   Author: Chip Turner
   Provide: Math::GMP version 2.04
   Repo: uwinnipeg
   CPAN: http://search.cpan.org/dist/Math-GMP-2.04/

[download]

The same may be true for 5.10 32-bit (but not for 64-bit:().

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
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In reply to Re: How to Install Math::GMP in Windows by BrowserUk
in thread How to Install Math::GMP in Windows by sthirumalai

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