You should be able to see the full header info in Yahoo by clicking on the little arrow just under the basic header info, and that might show an IP address of the sender.
Here ya go, the whole header, I am 99% sure I know who it is. Let's see if the sleuths who track IP addresses come up with the same answer:
X-Apparently-To: bandaches@yahoo.com via 209.191.106.87; Wed, 01 Dec 2010 19:02:51 -0800
Return-Path: <zombieclone1@hotmail.com>
Received-SPF: pass (mta195.mail.ac4.yahoo.com: domain of zombieclone1@hotmail.com designates 65.54.51.92 as permitted sender)
X-YMailISG: dZBMWsscZApH3HcSI2ZZHdfwSXk68Ts2CSMaoOwVkVmTyfw7 OAPOM.a6LzaTvhuiEGT3OVViNnQ.Pdj31zUXBgUQIVCouLNeevcSWx6yvMC_ 7lzgQwUYp.E9M49vn8kBaj2rH_TmrZA_75lLYEIPKvt2f0vLDsus4j8rwDaP EGoHyEcR6ZzBb0RZknfu20pUm6OFJ9HHPiM8FKaRFbeGMIxo5uXL0.IRuP3n _vzhgEVE9abK33O0oNio7q_49_7j5pKTrZXT__2a_C7PH5Mngj2JrPtLvDbe eksebsweVqGIZYfi5gDi6ZwkGxF.5uwu5jTppxClI7xKZ01Np1A4trNipRC7 m4vwtZuXLudYeS_kNte2eXO3ckCLsg8_EDlRtK7BZeoF9KylG_FAgfv99gT3 zALROGlrpQW9xviaTXuJHjgZBXxBYDsiBIHkGrT2YbJMBUn53j76m0nsjIJZ iMgX9jVQqBoA.CLADMo_m9Zq7qjVPO1gvMRsnwWIYTjQyDaM1OQtJ6kIfMiu lY2d_QvIYD9xtpjLfzNy3lbRDzscYpsTx.cGvQdlKR9c1b0E6kcSZSXDuHoc lsKlQ8KgggCt.ob9KhKYmHXsYoJs2QZp2M0VfZLDzoIcj0g8DOhsIC8ihGkG cmkwuajX2RCPFz_enCYy7dWwdf5zdGOXq7Z9oLWQCaDk4KuV.jEiguZ__dEy exe4q7BXa289vAtF3nDfiR1XOleTA0yrJstpA70op.Yd7CoNT5Lop4l_Jh8m eDpZasmRbSruY38q6zNKKjQ3VZsKup0gNn4bAkOmCdDQZEBfQolImc_f6Ahq ZvGvXpejwRJft1qWO8OVLOISY8Q16FoYf5pHszxGR0qrlUC8X0n5EguIOtqt o2MNmLScUM3YN9utbSFC0IHlqYkB_UoPiwYnYzPJaE3nSC7H77CFwVa3uAcy OO5z2JtlwpQBrDVVKQHfBT2xpv7208NKVKOk8qupYPu7I131OplSCoFnpyrZ nv213WZY2IUZ11eCCBhTA0n85.22Aw631b1GZlfhwNZGCk4jUz7M3p3eXUBv l_qg0UQE0cqFMqj2t1oCQ08y6xsMJwNdKg2Nb.MjgmLCQg8Cu8I3k3T0Ffa2 IzyscbwqirLs1bdD_qxPrG8XJvY27wrFVsxPmF1hz1bYvupNcmG.HISiLUyN jgS0TjdAY_ZhQn3Nk2Whkl3inl81HQlz0SWCtlEFHv9eGDXZYPvFbzVtMOPW 8PUVji5zt_i2KOjRuw7JBVssskg1Oomn0dDbYgdkV95fS6UGhRr1d.mnKn2W G.1PAzBZd6TtGZK0XTfJHP8CgweG0adCDBJ2qx474j97gqLg5_x38PjjB1Jb N3V5406h2W.nPzJrbtVtsmUlj_AjkD.DgJpjag--
X-Originating-IP: [65.54.51.92]
Authentication-Results: mta195.mail.ac4.yahoo.com from=hotmail.com; domainkeys=neutral (no sig); from=hotmail.com; dkim=neutral (no sig)
Received: from 127.0.0.1 (EHLO snt0-omc4-s41.snt0.hotmail.com) (65.54.51.92) by mta195.mail.ac4.yahoo.com with SMTP; Wed, 01 Dec 2010 19:02:51 -0800
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Message-ID: <SNT135-w3299525F24650C46F02EC83270@phx.gbl>
Return-Path: zombieclone1@hotmail.com
Content-Type: multipart/alternative; boundary="_d9a1aba1-06e4-4c08-bf0f-c8a80edbcab9_"
X-Originating-IP: [75.16.244.31]
From: Zombie Clone <zombieclone1@hotmail.com> Add sender to Contacts
To: <bandaches@yahoo.com>
Subject: It's me you stupid fuck!
Date: Wed, 1 Dec 2010 21:02:23 -0600
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X-OriginalArrivalTime: 02 Dec 2010 03:02:23.0065 (UTC) FILETIME=[57637490:01CB91CD]
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