OK...
Load time in between maps have various different components.
1. Loading Game data to memory. All the information for the new map has to be extracted from compressed files on your hard drive and loaded into memory.
This data is the map itself, the vehicles, the guns, the player models etc.
Remember that the patches since the game was released have added to this data.
The time this takes is effected by many factors on your PC. The amount of RAM you have is a factor as RAM is faster than pagefile, and therefore loading data into RAM takes less time, and unless your pagefile is on a different physical disk then your BF2 install then loading data to pagefile is reading and writing to the same disk which is slower again.
The speed of your hard drive is also a big factor.
A single slow IDE hard drive is going to do all this work slower than say a pair of SATA2 Raptors in RAID-0.
BF2 loads around 1.5Gb of data into memory, the more of this that goes into RAM the faster the load times will be.
As the data is coming from a compressed source there is also a CPU hit to turn it into the raw data that the game uses.
Try having Task Manager open when BF2 is loading a map and see if the CPU peaks out.
If your CPU ever hits 100% then there is a bottle neck in your system.
2. Loading Game Graphics to video memory. All the frames, textures and pretty things you see in BF2 also need to be loaded into video RAM.
Again the more and faster your video memory the quicker the load times will be.
A 256Mb graphics card will be fine for playing BF2.
3. Verifying Client data. Is a check run between the client [your PC] and the server to make sure the files you are running are the same as the ones the server is using.
This is, as "mcfarmer.dk" said, a security measure to make it harder for people with modified data to join games that are not modified.
It should be noted that it is not a ranked server requirement to have the verify, as punkbuster checks will still take place, but the vast majority of ranked servers do verify.
As these checks are going between the client and server there is internet bandwidth usage, and a slow, or heavily used connection can cause this to take longer.
These checks are being run on the files in memory, and again the amount of RAM, and or hard drive, you have will effect the speed of these checks.
A 512Kbs connection should not be a bottleneck for the verify, as long as there is not a lot of other internet traffic.
To review...
Get 2Gb or RAM.
Get the fastest hard disks you can afford [I like Western Digital Raptors].
Your GPU has enough RAM, should be able to play a mix of medium and high without AA.
Your internet connection is fine, as long as you are only using it for BF2,ie not downloads, P2P, file sharing. Things like Teamspeak etc will be fine.
Hope this info helps dude.
DrM