Yep, i've got the same problem. I use USRobotics for my wireless though. I have read lots of things on the apple forums about it... there are threads all over it. Seems that its a 10.5.2 problem. A lot of the fixes seem to involve trying to change settings on the wireless access point though (security settings etc), which is not really a fix as a laptop should be able to conect to any network (that it has access to) without problem. You shouldn't need to change the settings on the wireless access point at all.
Some of the fixes might work and make your own wireless network more stable for you, but it seems the underlying problem will still be there.
The thing i'm unsure about is whether this is purely OS? or hardware related too? I get the same problem in OSX and in XP Pro via bootcamp (although thats obviously using apples drivers for the wireless). I'd hate to think that these latest macbook's have a dodgy wireless card in them.
I'm new to apple's but thought i'd give them a try. I've got the latest macbook (black one), couple of months old now. I like OSX, but this wireless issue is very annoying and is actually making me think about selling my macbook, and getting something else.
What's also annoying is that i dont think Apple have officially admitted its a problem yet, so are not officially going to fix it.
Anyone have any idea when the next update to OSX will be out? (maybe with a fix). I mean are we talking near future? weeks? months? next year? I know this will only be a rough estimate, but i've only had an Apple for a few months and have no idea, whereas some people on here have had apples for years and will know how often they release updates etc.
If its not fixed in the next update, i reckon i'll be going back to an XP laptop.
Cheers.