Given below MOSS 2007 service account passwords change steps
To Update Central Administration application pool Password
Update the password for the account that is used by the Central Administration application pool. To do this, follow these steps:
On all servers in the server farm, open a command prompt, type the following line, and then press ENTER:
cd %commonprogramfiles%\Microsoft Shared\Web server extensions\12\Bin
On the server that hosts the Central Administration Web site, type the following line at the command prompt, and then press ENTER:
stsadm -o updatefarmcredentials -userlogin DomainName\UserName -password NewPassword
On all other servers in the server farm, type the following line at the command prompt, and then press ENTER:
stsadm -o updatefarmcredentials -userlogin DomainName\UserName -password NewPassword -local
Restart Microsoft Internet Information Services (IIS) 6.0. To do this, type the following line at the command prompt, and then press ENTER:
iisreset /noforce
To Update application pool account
Update the password for the application pool account that is used by Web applications on the server farm. To do this, type the following line at a command prompt on every server on the server farm, and then press ENTER:
stsadm -o updateaccountpassword -userlogin DomainName\UserName -password NewPassword –noadmin
To Update Shared Service Password
Update the password for the account that is used by every Shared Services Provider (SSP) on the server farm. To do this, type the following line at a command prompt on every server on the server farm, and then press ENTER:
stsadm.exe -o editssp -title SharedServicesProviderName -ssplogin DomainName\UserName -ssppassword NewPassword
To Update Search Service Password
Update the password for the account that is used to run the Office SharePoint Server Search service. To do this, type the following line at the command prompt, and then press ENTER:
stsadm.exe -o osearch -farmserviceaccount DomainName\UserName -farmservicepassword NewPassword
To Update Single Sign On Service account Password
If the server farm is configured to use single sign-on, update the password for the account that is used by the Microsoft Single Sign-On Service. To do this, follow these steps:
Click Operations in SharePoint 3.0 Central Administration, and then click Service accounts under Security Configuration.
Under Windows service, click Single Sign-On Service.
Under Configurable, specify the password, and then click OK.
For more details visit : http://support.microsoft.com/default.aspx/kb/934838