Some times when the solution deployment got stuck in the list and shows "Deploying" for a long time, we will have to cancel it and maybe re-deploy it again.
First we need to get the deployment id:
stsadm -o enumdeployments
<Deployments Count="1">
<Deployment JobId="7bf469db-66cd-4333-9fe8-ddeb0c138466">
<Title>Windows SharePoint Services Solution Deployment for "abc.wsp"</Title>
<Type>Upgrade</Type>
<State>Active</State>
<File>abc.wsp</File>
<ServerType>Front-end Web server</ServerType>
</Deployment>
</Deployments>
Notice the JobId you got.
Next, cancel the deployment by the JobId above:
stsadm -o canceldeployment -id 7bf469db-66cd-4333-9fe8-ddeb0c138466