Any ideas on why my internet data speeds slow down from DSL speeds to dial up speeds when I connect the aircard (Verizon 727 USB) to my Cradlepoint MBR 1000 wireless router ?

If I plug the aircard into the laptop directly, the speeds are fast, better than DSL.

I'm wondering if I have some sort of conflict or have set some feature wrong with the laptop wireless card or in the Cradlepoint router.

It's a dramatic slow down.....

Is the Cradlepoint sitting in the same location as you have the USB727 or somewhere else?  Normally the modem sees two signals, a 1XRTT (2-3 times dial-up) and an EVDO (broadband) and they could be different strength.  If the EVDO is marginal it might work where your computer is, and the USB727 is when hooked directly, but might not work were the router is and use the 1XRTT signal.

Talk to who you bought the Cradlepoint, they should be able to help you.  I know 3GStore.com does this kind of support when they sell them.

I see no speed differences between my UM150 in the computer or in my Cradlepoint 1000.

Bear, the other item you might check and eliminate as a possible source of your slow down is the PC to Modem wireless connection. With the air card in the modem, use a cat5 network cable to hardwire your pc to the modem and see if the results are different than over a wireless connection. I don't use an MBR100, but a KR2 which is very similar. I haven't experienced this issue, but some users have found that the wireless connection is somewhat slower, depending on location and distance. Others have claimed slow downs based on different wireless security option settings.
As Bill said, if its nothing obvious and you suspect the modem, call the support guys at 3Gstore, assuming thats where you bought. 

Thanks for the suggestions. I called 3G Store (bought the stuff from them) and was a little disappointed by their customer support. The tech made a couple of suggestions, but I was hoping he would walk me through checking settings on the router and my wireless card to make sure I had made the correct settings. He did suggest that I may need to upgrade my wireless connection from an 802.11b to a 802.11n since the router is 802.11n. He said this should increase my speed. He indicated that's why the speed is good when the air card is plugged directly into the laptop vs. using the air card in the router. The problem I have with this suggestion is, I remember having a very fast connection at one point, even when I had the air card in the router. So I'm going to reset everything and start from scratch, to see if I can find the point where I had the fast speeds...I think it was right before I added the security setting in the router. If I still have slow speeds then I'll get a 802.11n adaptor to plug into my laptop. The 3g tech did offer to go through my settings once I got an 802.11n adaptor.

I am sorry but the 3GStore tech has no clue.  802.11b is faster than the Verizon internet connection so going to 802.11g or 802.11n will not speed up your internet connection.  Sending files between computers on the network will be faster, but not the internet speed.   If the tech would have gotten me I would have tried to get to a supervisor.
Break the problem down and see if you can figure out what is going on.