I am using ubuntu ultimate edition 2.2. I have problem in installing mysql.
this is the error message that i receive while installing mysql .

"""
sudo apt-get install mysql-server
[sudo] password for home:
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
mysql-server-5.0
Suggested packages:
tinyca
The following NEW packages will be installed:
mysql-server mysql-server-5.0
0 upgraded, 2 newly installed, 0 to remove and 0 not upgraded.
Need to get 0B/23.6MB of archives.
After this operation, 79.5MB of additional disk space will be used.
Do you want to continue [Y/n]? Y
Preconfiguring packages ...
(Reading database ... 400333 files and directories currently installed.)
Unpacking mysql-server-5.0 (from .../mysql-server-5.0_5.1.30really5.0.75-0ubuntu10.2_i386.deb) ...
Aborting downgrade from (at least) 5.1 to 5.0.
dpkg: error processing /var/cache/apt/archives/mysql-server-5.0_5.1.30really5.0.75-0ubuntu10.2_i386.deb (--unpack):
subprocess pre-installation script returned error exit status 1
Selecting previously deselected package mysql-server.
Unpacking mysql-server (from .../mysql-server_5.1.30really5.0.75-0ubuntu10.2_all.deb) ...
* Stopping MySQL database server mysqld [ OK ]
Errors were encountered while processing:
/var/cache/apt/archives/mysql-server-5.0_5.1.30really5.0.75-0ubuntu10.2_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)


"""

I also got a message stating that installed packages have unmet dependcies

so i ran command
"sudo apt-get -f install" and got the following output

"""
home@laptop:~$sudo apt-get -f install
Reading package lists... Done
Building dependency tree
Reading state information... Done
Correcting dependencies... Done
The following extra packages will be installed:
mysql-server-5.0
Suggested packages:
tinyca
The following NEW packages will be installed:
mysql-server-5.0
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
1 not fully installed or removed.
Need to get 0B/23.6MB of archives.
After this operation, 79.4MB of additional disk space will be used.
Do you want to continue [Y/n]? Y
Preconfiguring packages ...
(Reading database ... 400336 files and directories currently installed.)
Unpacking mysql-server-5.0 (from .../mysql-server-5.0_5.1.30really5.0.75-0ubuntu10.2_i386.deb) ...
Aborting downgrade from (at least) 5.1 to 5.0.
dpkg: error processing /var/cache/apt/archives/mysql-server-5.0_5.1.30really5.0.75-0ubuntu10.2_i386.deb (--unpack):
subprocess pre-installation script returned error exit status 1
Errors were encountered while processing:
/var/cache/apt/archives/mysql-server-5.0_5.1.30really5.0.75-0ubuntu10.2_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
"""

i would be happy if any one helps ...

I think your basic issue is
ie you already have 5.1 installed... Do you really want to go back to 5.0?
If you do, you'll need to uninstall 5.1 first.

thanks