As noted above, some states (like Pennsylvania) require you to maintain both a Medical training license AND a Medical Doctor (the unrestricted) license.
Since you won't be eligible for the unrestricted license until you have completed a full year of post-grad training in most states, you will have to renew your MT license (since it expires in late June) before applying for the MD license. The cost for our MT license in PA is only $15. The cost for the MD was around $100 as I recall.
In regards to the DEA number, you should have an institutional one for which you can write scripts. To get your own you must have an unrestricted MD license. The numbers are generally renewed every 2 years on even years and cost around $400. If you apply for it during the middle of the 2 year period, you will only have the number for the remainder of the time. For example, the 2 year period this time around started at the end of December 2005/Jan 2006. Although I was eligible summer of 2005, if I had applied for the DEA at that time, the number would have only been good until the end of 2005 at which time I would have had to reapply (and pay another $400). So, if you fall between period (the next will be end of 2007) it might behoove you to wait so that you get the maximum usage out of the number before having to reapply and pay.