You could do this two ways the easy way or the hard way.
The easy way
Once you install these programs all you need to do is just run these programs and from there install the app's you want. They are downloaded from Internet through what ever connection you have on your computer and put on your iphone which is docked to a computer.
Both the programs are pretty easy once you install you will get the idea. Iphone PC suite app's page is in Chinese but you will get your way around it by copying what ever you want to translate into Google and do it that way.
The hard way
Some times if you are on 1.1.3 or 1.1.4 you will have issues with ibrickr so you can't install that way so how to install app's now. This takes bit of work on your part.
First of get to the sources that's where you will get the app's from. Now go to source URL in your safari browser on the computer and you will get a text based page. Search for the app you are looking for on the page and you will get the link. Once you find the link copy that link and download the file. Usually it will be a .zip file, unzip it and it will have a folder saying the app name and .app which is the app. And there will be a read me file or something extra don't worry about those. Use the iphone PC suite file manager and get into the iphone or any number of other ways to get into the iphone file system of your iphone. Look for the application folder which should be the first one on the list.
Copy the .app folder into that folder and you are done. Now just change the folder settings and give it all the read and write permission which you can do by clicking on the folder and selecting properties. Give all the permissions if you are confused. Once you do this you are ready to run the app on the iphone. If the app doesn't appear on the iphone just restart the iphone and they will appear.
So hope these both ways will help you get app on the iphone without wifi and using the costly and slow gprs.