how can you view an HTTP request in transit?

In order to capture packets "out in the ether" you need to be able to control the endpoint or the medium in which the communication is operating. In the case of wired connections, you need to control the server, switch, router, etc, or tap into the line directly. In the case of wifi, you can use wireshark as @schroeder has mentioned coupled with your wifi card. The problem here is that if the wifi router uses encryption, then without effort you will only be able to see your own traffic. As for your own usage, depending on your operating system, you might find http://fiddler2.com/fiddler2/ to be a much lighter-weight and easier to use/understand debugging proxy for Windows. Start it up and Chrome should automatically use it. All requests can go through there. And to top it all off, you can introduce an SSL certificate to allow you to decrypt your HTTPS sessions.

You can use any packet sniffer that you are comfortable with, the main feature allowing you to listen all packets at Ether belonging to your network is http://en.wikipedia.org/wiki/Promiscuous_mode. Normally, tools like Wireshark allow to listen in promiscuous mode at ethrent w/o any external config. But even if its not working, you can search for your NIC to be configured in promiscuous mode (given it supports that).

A slight aside, but in the OP's specific case of viewing a web page in chrome: you can hit f12, or ctrl-shift-i to bring up the developers tools and click on the network tab. Refresh the page to see a list of all network requests made by the browser. Click an individual request in the list to see details of that request.

What you are looking for is a man in the middle attack. A man in the middle attack is when someone between you an the server is reading/modifying your communication. Some know methods of archiving this is: arp-spofing. arp-spoffing is used on local network to insert you in the communication between your target and your gateway to the internet. http://www.oxid.it/cain.html is a tool that can do this and can also find passwords and usernames from unencrypted connections dns-spofing. a url like www.google.com translates to a ip by dns. so if you control the dns you control where all url points. So then you point all sites to your computer and make it act like a proxy.

Can I suggest using scapy for this? I have a post on Stack Overflow talking about how to do this. Not sure how much programming experience you have but this solution should be plug and play after you get Scapy and Python installed on the box. What this will provide is an easier and quick snapshot of each and every http request you make on your box without needing to stop and drill down into a packet. Please see http://stackoverflow.com/questions/10184016/complete-http-get-with-scapy/10205888#10205888

I think the best way understand how easy is to sniff HTTP traffic is read about http://en.wikipedia.org/wiki/Firesheep With WiFi access you don't need to seat on the wire any more.

Another great tool that hasn't been recommended is http://mitmproxy.org/. It lets you: Intercept and modify HTTP traffic on the fly Save HTTP conversations for later replay and analysis Replay both HTTP clients and servers Make scripted changes to HTTP traffic using Python SSL interception certs generated on the fly