Microsoft has WSUS which is great for the Microsoft products it supports (and it doesn't support all Microsoft products), but in reality companies have many applications from other vendors.
Is there a patch/update management server similar to WSUS, but that works with lots of vendors or developers?
Update
Some good soul decided to change the server tag to a Windows tag - Note that this is NOT just for Windows. If you know a good patch server that runs on Linux or Apple then those are perfect too.
Shavlik's NetChk Protect could be a good option for you. The company has a close relationship with Microsoft and its underlying technology powers Microsofts own Baseline Security Analyzer product. Whilst Microsoft's MBSA only supports patching Microsoft products NetChk Protect support products from many other vendors.
There are quite a few products out there which support this LanDesk, Altiris and PatchLink to name a few.
To the best of my knowledge all the products out there are walled gardens.
BigFix enterprise is also quite a good patch management system, and has a lot of "third party" patches as well as all the normal MS patches.
I think conceptually it's better than WSUS as well - you tell the clients when to update, rather than the clients checking back to see if any updates are needed.
I'm sure it's not the best but HP System Insight Manager looks after hardware alerts etc. and also can manage updates. Like I say it may not be the best but at least you have another option to investigate.
We use Lumension's (formerly Patchlink) Patchlink software for updates.
http://www.lumension.com/vulnerability-management/patch-management-software.jsp?rpLangCode=1&rpMenuId=150833
Works well, lots of reporting capabilities via Patchlink Enterprise Reporting Server, which takes advantage of SQL Reporting Services. Worked well for us thus far and with SQL backend lets me roll my own reporting solutions if needed.
WPKG can be used this way. The process will be rather manual, but it is open source so there's no reason why you can't write a script to monitor the sites you want to download patches from and roll them in. I bring WPKG up because it's just too easy to get running.
Since you seem to like WSUS, you can consider the WSUS + EminentWare's WSUS Extension Pack. The WSUS Extension Pack provides additional update management control, scheduling, machine selection, etc. and excellent reporting capabilities. More importantly, it allows you to extend WSUS to deploy and manage 3rd party or non-Microsoft patches and applications. Essentially you create packages that allow you to extend WSUS to deploy any MSI, MSP or EXE.
You can also use a applications like Server Automation from HP, who can patch and install OS/applications, on Windows/Linux/AIX/Solaris/HP-UX and so on..
But that a really expensive product and usefull only starting with at least 1000 servers growing to 15k servers.
PS: I am working for HP.
I've used Numara Patch Manager, and it supports a ton of Microsoft apps as well as a few other smaller utilities from Adobe, Apple, Mozilla, etc. They do offer a trial download.
IBM Tivoli Provisioning Manager (formerly called Tivoli Configuration Manager) is multi-platform and can deploy patches, applications, system changes, etc. It can also be configured to remove applications.
There are two catches. First is complexity. Second is cost.
Because it is multi-platform and is extremely customizable, it doesn't do a lot out of the box. It also carries a price tag that would make a small-to-medium sized company clutch its chest.