Sorry this is one I failed to blog which released while I was at MMS http://support.microsoft.com/kb/950853/en-us .This hotfix is strongly  recommended for for those running the Exchange 2007 MP together with http://support.microsoft.com/kb/951979/en-us 

SYMPTOMS

Consider the following scenario:

•You import the Microsoft Exchange Server 2007 Management Pack for Operations Manager 2007 into a management group in Microsoft System Center Operations Manager 2007 Service Pack 1 (SP1).

•Then, you install the Operations Manager 2007 agent on an Exchange Server 2007 computer to monitor Exchange rules and processes.

In this scenario, a memory leak occurs on the Exchange Server 2007 computer.

RESOLUTION

Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that is described in this article. Apply it only to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Operations Manager 2007 service pack that contains this hotfix.
To resolve this problem immediately, contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support (http://support.microsoft.com/contactus/?ws=support)

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Hotfix installation information

You must apply this hotfix on all Operations Manager Management Server computers. You can apply this hotfix from Windows Explorer or at a command prompt. This hotfix package includes both 32-bit and x64 file versions. When you apply this hotfix, it will install the files versions that are appropriate to your particular installation.
The computers that are running the agent are updated automatically. However, you must approve the update in the Pending Management folder. To do this, follow these steps:

1.
On the computer that is running the management server role, click Start, point to All Programs, point to System Center Operations Manager 2007, and then click Operations Console.

2.
Select Administration view, expand Administration, expand Device Management, and then click Pending Management.

3.
In the Pending Management folder, review and approve the agent computers on which you want to apply this hotfix.

Prerequisites

You must install Operations Manager 2007 Service Pack 1 before you apply this hotfix. To download the Operations Manager 2007 Service Pack 1 Upgrade Package, visit the following Microsoft Web site:

http://www.microsoft.com/downloads/details.aspx?FamilyId=EDE38D83-32D1-46FB-8B6D-78FA1DCB3E85&displaylang=en (http://www.microsoft.com/downloads/details.aspx?FamilyId=EDE38D83-32D1-46FB-8B6D-78FA1DCB3E85&displaylang=en)

Restart requirement

You do not have to restart the computer after you apply this hotfix package. However all Operations Manager services will be automatically restarted.

Hotfix replacement information

This hotfix does not replace any other hotfixes.