Converting documents to Word or Open Office e.t.c is a pain if you need to do them occasionally, even more true for people who use Mac and Linux and don’t have Microsoft office. Usually one is not sure how their resume would look on MS office if they created the document on Open office or iWork or any other non Microsoft product (unfortunately majority of the world use Microsoft 
) . These cross platform issues would be easier if there was just one format, but that wouldn’t help Microsoft mint money would it? If you are going to convert files occasionally , there is no point searching for a separate application and having it add to the clutter on your computer. All these hassle could be easily taken care with a Google account.
Here’s how it works :
Just upload your document Word or Open office or TXT to Google Docs. (you need to be logged in to your Gmail or Google account)
Open the document you just uploaded to convert , then using the Download as option under the file menu to convert the document as a HTML or PDF or RTF or txt or DOC or ODT.
Now you have converted the file to your required format with a bonus of safely backing up the document on Google’s servers for future use. If you don’t wish to back up you need to remove the file manually.
Google does a great job converting word or open office formats to PDF, but the reverse (PDF to Word or txt etc) is just very basic and minimal. May be you should try here for some better PDF to word conversion. Also note that password protected documents are still not supported for upload into Google docs and hence conversion wouldn’t be possible as well.
While Google Docs would help solve your occasional file format problems, If you require something really advanced and offline, I suggest you look at standalone application for that specific file format conversion based on your platform (Mac, Linux, Windows, e.t.c).
If you didn’t already know, you can save your documents to PDF and Open office format using Office 2010 using the save as option. Office 2007 don’t and before versions of Microsoft office don’t allow this.
If you are looking for a specific convertor to convert your files (any format) to PDF, you should try this Open source application called PDF Creator . Please note that PDF Creator is available only for windows as of now.
Feel free to tell me if this post was useful. I would be glad to hear if you have a better alternative.