During the Microsoft Exchange 2007 install we will create the default address lists and offline address lists. During that creation time we will populate the msExchResourceAddressLists attribute on the organization configuration object with the DN of the All Rooms address list.

This allows the All Rooms address list to be shown in the OWA when you click on the address list tab. Running the following Powershell cmdlet [Get-OrganizationConfig] will let you see that after you delete the All Rooms address list it is no longer linked.

[PS] C:\>Get-OrganizationConfig

Name : org
LegacyExchangeDN : /o=org
Heuristics : None
JournalingReportNdrTo :
ResourceAddressLists : {All Rooms DEL:47dd20dc-2efa-462b-b838-369eac589ddd}
IsMixedMode : False
ManagedFolderHomepage :
ForeignForestFQDN : {}
ForeignForestOrgAdminUSGSid :
ForeignForestRecipientAdminUSGSid :
ForeignForestViewOnlyAdminUSGSid :
ObjectVersion : 6903
SCLJunkThreshold : 4
MimeTypes : {text/html;htm, text/html;html, text/plain;tx
t, text/css;css, text/iuls;uls, text/scriptle
t;wsc, text/webviewhtml;htt, text/x-component
;htc, text/x-vcard;vcf, text/xml;xml, image/g
if;gif, image/jpeg;jpg, image/x-xbitmap;xbm,
image/bmp;bmp, image/pjpeg;jpg, image/png;png
...}
MicrosoftExchangeRecipientEmailAddresses : {X400:C=US;A= ;P=org;O=Exchange;S=MicrosoftExchange329e71ec88ae4615bbc36ab;, SMTP:MicrosoftExchange329e71ec88ae4615bbc36ab6ce41109e@org.local}
MicrosoftExchangeRecipientReplyRecipient :
MicrosoftExchangeRecipientPrimarySmtpAddress : MicrosoftExchange329e71ec88ae4615bbc36ab6ce41109e@org.local
MicrosoftExchangeRecipientEmailAddressPolicyEnabled : True
MinAdminVersion :
AdminDisplayName : {335A1087-5131-4D45-BE3E-3C6C7F76F5EC}
ExchangeVersion : 0.0 (6.5.6500.0)
DistinguishedName : CN=org,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=tpworld,DC=local
Identity : org
Guid : 847045b0-036f-42c1-86f5-846c6f9fb0eb
ObjectCategory : org.local/Configuration/Schema/ms-Exch-Organization-Container
ObjectClass : {top, container, msExchOrganizationContainer}
WhenChanged : 12/5/2007 1:22:22 PM
WhenCreated : 3/23/2007 11:06:54 AM
OriginatingServer : GC01.tpworld.local
IsValid : True

How to fix
1. Open ADSIEdit.
2. Naviagate to the All Rooms address list.
3. Copy the distinguishedName attribute.
4. Open your organization object [cn=YourOrg].
5. Look in the list of attributes for the msExchResourceAddressLists attribute.
6. Remove the current DN which is {All Rooms DEL:47dd20dc-2efa-462b-b838-369eac589ddd}.
7. Paste in the new distinguishedName attribute of the All Room's address list.

NOTE: If you have multiple domain controllers you need to replicate them around.
8. Run Get-OrganizationConfig to verify that the changes have taken place.

[PS] C:\>Get-OrganizationConfig

Name : org
LegacyExchangeDN : /o=org
Heuristics : None
JournalingReportNdrTo :
ResourceAddressLists : {All Rooms} <-- Fixed!!
IsMixedMode : False
ManagedFolderHomepage :
ForeignForestFQDN : {}
ForeignForestOrgAdminUSGSid :
ForeignForestRecipientAdminUSGSid :
ForeignForestViewOnlyAdminUSGSid :
ObjectVersion : 6903
SCLJunkThreshold : 4
MimeTypes : {text/html;htm, text/html;html, text/plain;tx
t, text/css;css, text/iuls;uls, text/scriptle
t;wsc, text/webviewhtml;htt, text/x-component
;htc, text/x-vcard;vcf, text/xml;xml, image/g
if;gif, image/jpeg;jpg, image/x-xbitmap;xbm,
image/bmp;bmp, image/pjpeg;jpg, image/png;png
...}
MicrosoftExchangeRecipientEmailAddresses : {X400:C=US;A= ;P=org;O=Exchange;S=MicrosoftExchange329e71ec88ae4615bbc36ab;, SMTP:MicrosoftExchange329e71ec88ae4615bbc36ab6ce41109e@org.local}
MicrosoftExchangeRecipientReplyRecipient :
MicrosoftExchangeRecipientPrimarySmtpAddress : MicrosoftExchange329e71ec88ae4615bbc36ab6ce41109e@org.local
MicrosoftExchangeRecipientEmailAddressPolicyEnabled : True
MinAdminVersion :
AdminDisplayName : {335A1087-5131-4D45-BE3E-3C6C7F76F5EC}
ExchangeVersion : 0.0 (6.5.6500.0)
DistinguishedName : CN=org,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=tpworld,DC=local
Identity : org
Guid : 847045b0-036f-42c1-86f5-846c6f9fb0eb
ObjectCategory : org.local/Configuration/Schema/ms-Exch-Organization-Container
ObjectClass : {top, container, msExchOrganizationContainer}
WhenChanged : 12/5/2007 1:22:22 PM
WhenCreated : 3/23/2007 11:06:54 AM
OriginatingServer : GC01.tpworld.local
IsValid : True

9. Have your users log out of OWA and log back in and when they click on the address list tab they should now see the All Rooms address list.

Dave