I'm not sure what to make of this thread!
Bomberman, the only way to get x-sync at 1/800sec is with High Speed Sync enabled. Your 430EX can do this, it can even do it remotely via E-TTL (it's second-curtain sync you can't do remotely) using a 580EX or ST-E2 as Master but you will almost certainly not have enough power working this way. HSS gobbles power and cuts flash range (as distinct to triggering range) quite dramatically. Pocket Wizards or Radio Poppers will not help with this, not even the new E-TTL jobbies.
However, you should be able to do it at normal x-sync speed because, as said above, it is the flash duration that becomes your
effective shutter speed and that will always be shorter than 1/800sec, more like 1/2000sec or even less depending on the power required.
Your normal max x-sync speed is 1/200sec and this is retained using E-TTL remotely and with the top end radio triggers like Pocket Wizards. Yongnuo RF-602 and other cheaper triggers cause a delay though, and you'll need to use 1/125sec with them. This might not be a problem though, as you'll still get the very short flash duration.
You won't be able to work in bright daylight though, not without getting ghosting. Only HSS can get around that and as I say I'm pretty sure you won't have enough power for that with just one 430EX. On the other hand, I've seen plenty of biking pictures shot like this with visible ghosting and I think it adds to the effect. You'll need to try it. There is also the clever Hypersync mode on the new Pocket Wizards (for a price, and if you can get them to work) that increases the x-sync speed but you will only go up from 1/200sec to 1/350sec or so at best; it helps, but will only reduce the ghosting a bit, not eliminate it.