Intel Xeon family is currently comprised of E3, E5 and E7 subfamilies, that target uni-processor, dual/quad- and multi-processor systems respectively. Current generation of Xeon E3 and E5 microprocessors was released in the course of three months, from March to May 2012. Future Xeon E3s and E5s will be introduced more gradually, with the E3 processors available in May or June 2013, while some E5 series chips will be pushed back as far as Q1 2014. Ivy Bridge-based Xeon E7s are also expected in the second half of this year. All in all, within the next 4 quarters all three Xeon subfamilies are going to move to newer microarchitecture.
Xeon E3-1200 CPUs will be based on Haswell architecture, and so it's not surprising that they are planned to launch simultaneously with the first desktop Haswell processors. Sometime from May 27 to June 7 Intel will introduce 13 different E3 SKUs. Xeon E3-1220 v3, E3-1225 v3, E3-1230 v3, E3-1240 v3, E3-1245 v3, E3-1270 v3, E3-1275 v3, E3-1280 v3 and E3-1285 v3 will have standard power requirements. The E3-12x5 v3 models will feature on-chip graphics, whereas E3-12x0 models will not. Intel will also launch four low-power Xeons: E3-1220L v3, E3-1230L v3, E3-1265L v3 and E3-1285L v3.
Xeon E5-2600 v2 family for two processor servers will be available in Q3 2013. These parts will be based on Ivy Bridge-EP core, and they will be compatible with socket 2011. Xeon E5-4600 v2 CPUs for the same socket, but supporting 4-way processing, will be released in Q1 2014. Also in the first quarter 2014, Intel is going to launch E5-2400 v2 "Ivy Bridge-EN" microprocessors for socket 1356.
Second-generation Xeon E7 CPUs are currently scheduled for Q4 2013.
Update (March 24): We forgot to mention Xeon E5-1600 v2 series, designed for one-way workstations and servers with socket 2011. These processors will be available at the same time as E5-2600 v2, in Q3 2013.
Related News (newer articles):
Jul 30, 2013: Launch schedule of Intel Xeon server processors
Jun 05, 2013: Intel introduces Xeon E3-1200 v3 server processors
Apr 02, 2013: Some details of upcoming Intel Xeon E5 v2 and E7 v2 CPUs
Mar 27, 2013: Details of Xeon E3-1200 v3 "Haswell" processors