Sporadic no internet access in Safari, Skype works

Hey guys,

First - sorry for my poor english. I switched to Mac some months ago, i have the newest type of a Macbook pro. It is connected by Wireless Lan (100Mbit) to the internet.

I have following problem:

Often i cannot load a page (google.com or ebay.com), or it is not completely loaded. In this time Skype is working without any problems (video chat). I tried to install Google Chrome to see if Safari makes the problem, but also here i get this effect.

Does somebody has a suggestion for me how i can find the problem? In Windows systems i know some ways like check in the task manager the usage of the network adapter

Achim